Ah, but that was 200+ years ago.
See, before the late 1700s punishment for crimes was more immediately brutal than it is today. This was because European and American cities didn't really have organized police forces. As a result, crime was easier to get away with unless someone was caught red-handed, and punishments were made harsh as a means of deterrence. Furthermore, the prisons that existed were generally small affairs attached to governmental buildings, made to hold people before trial. Jails, in other words. What you did was, you caught someone committing a crime, stuck them in jail, held the trial, and then put them in, say, the stocks, where they would be subject to public humiliation. Other punishments included whipping, branding, and frequently, execution.
The concept of holding people in chains for periods of years as a form of punishment had existed in ancient Rome, but had not been put in practice since the empire disintegrated. Nothing in Medieval Europe would have been able to sustain something like the Mamertine prison, where convicts were stuck in what was basically an offshoot of the sewer system. The Romans had enough resources to run something like that. The medieval world did not. The Romans set their prisoners to slave labor; Medieval Europe did not think of this.
Notice, also, that even this Mamertine Prison was built as an attachment to an already-existing structure. The concept of building something dedicated to the long-term confinement of convicts did not exist until the Bridewell House of Corrections was built in London. That was the mid-17th century.
The concept of indefinite imprisonment had existed for a while before then, but it was largely used for housing political prisoners. The "Oubliette", french for "Forgetting", was a place to toss someone you wanted to get rid of, and then forget about them. If the political prisoner was too high-class and powerful to risk this form of murder, there was the practice of gilded cages, where you could, say, imprison a King and his attendants, giving them all comforts but no exit. This was a function of the Tower of London since at least the reign of Edward II. Edward III imprisoned the King of France there during the Hundred Years War.
But, the Tower of London was not built as a prison; it was only adapted for that purpose. Oubliettes WERE built to hold people indefinitely, but they were small affairs, with the express purpose of getting RID of people in the cheapest manner with very little fuss, and they were attached to existing structures.
The Bridewell House of Corrections was something new. Built to house the vagrants and the "disorderly poor" (according to Wikipedia as of this writing), its function was to force people to work while they were imprisoned, as a means of teaching them skills and making them productive members of society when they got out. This building, and the institutions that followed it, presaged the modern concept of prison as a place of Reform.
But this was built as a means of housing essentially low-level offenders. The high-level offenders still got the stocks, the whippings, or the hangings.
People started to get sick of this in the 18th century. Juries kept refusing to convict people, on the basis of saving them from the awful punishments of the era. It was increasingly clear that the idea of draconian deterrence was not working. Not that this resistence stopped the implementation of the Sheep Laws, where even the smallest infraction was grounds for harsh punishment. The phrase "In for a penny, in for a pound" comes from this era, and demonstrates the fatal flaw in increasing the penalty for all crimes: people who do a small crime figure they might as well go for a big one, because the penalty is the same.
(This is what brought down the Qin empire 2000 years ago. A group of soldiers coming home late decided that if the penalty for tardiness was death, and the penalty for rebellion was death, they might as well rebel.)
So around about the end of the 18th century, people in Europe began to construct prisons as a means of housing high-level offenders for years or decades. Now that Europe was developing prototypical police forces, it was possible to catch people committing crimes on a greater scale, such that brutal deterrence was not necessary.
This was a reform movement. This was saving people from the brutality of the old system, giving them a place to stay, a place to work, a place to learn skills. People could be put in prison and held in England, or shipped to Australia. Much better for the soul than a public whipping (but worse for the body if you had no idea what creatures Australia had to offer).
The problem is, that was 200+ years ago. It's been centuries and the basic system hasn't changed. There have been tweaks, there have been improvements to conditions, there have been improvements to the means by which people are convicted and sent to jail, but the basic idea has not changed. In fact, the modern prison system has bits and pieces of all the old systems. We still throw people in prison and hold them there. We still throw them there was a means of state-sponsored revenge. We still work on the Roman model of subjecting people to slave labor, thinking that we're working off the basis of the House Of Correction model. We still forget about them once they're in there, as if the place is a giant Oubliette.
While the system was BETTER than what came before, that doesn't mean it is free of severe flaws. For one thing, the institution serves as a very convenient place to isolate all the people caught in the net of centuries-old bullshit ethnic politics. Which is to say, everyone who isn't White gets tossed in there while judges look at a rich White kid and go "aw, I can't ruin the boy's life. Do some community service."
And the system is actually getting WORSE, because the recent development of privately-run prisons has created spaces where prisoners are housed On The Cheap as a means of maximizing profits. Bland food is not given the least bit of spice; bad pipes remain broken; mold spreads and nobody does anything about it because -- well, it's a bunch of prisoners. Who cares about them? They're evil criminals. They deserve it, right?
Tell that to the poor slob who was imprisoned 30 years ago for having a bit of Crack in his hand. As the prisons have become worse, so has the sentencing. The system has become as cruel, and nearly as Draconian, as the old Sheep Laws. The system has bascially regressed to where it was in the late 1700s, before prisons were state-funded and held to a higher standard of cleanliness and justice. The system has devolved into its prototypical form AND adopted draconian sentencing. Towards people who aren't rich and White. At least Draco applied his laws evenly across the classes.
I write this today because it is a special occasion. A massive prison-labor strike started yesterday. All across the country prisoners are refusing to work, saying that they will not be made slaves. Prisoners, maybe. Slaves, no. They're not going to be made to work for 15 cents per hour so that some state or private company can have maximum profits at minimal cost.
And I have not seen this story on many news sites yet. Fox had a bit. Buzzfeed had a bit. Not Breitbart, not CNN, not NPR, not the New York Times. Maybe the story will blow up later. Maybe the people running the prisons will succeed in making us forget again.
It's so easy to forget them. We want to believe that the Bad Guy's story ends when he gets convicted, when he has the walk of shame out of the courtroom with cameras flashing as he holds his coat over his head. We want to believe that the best thing to do is to toss people into the dark box and forget about them, because that's just what they deserve. Heck, there's at least one kid's book series where the last page always has the giant heroic robot depositing villains directly in prison, no trial or anything.
It's basically the secular version of the Christian concept of hell. The bad guys go to hell or to prison, and we refuse to believe that maybe there's something better we can do for them. We approve of the devils within who poke at the damned souls with red-hot pitchforks. Because they deserve it, right?
The damned are rebelling against Hell. They will not permit themselves to be enslaved any longer, nor to let us be complicit in keeping Hell running. We who believe that the corrupt deserve the harshest punishments, whether religious or secular, are engaged in moral corruption ourselves for perpetuating this sytem. For letting slave labor continue to exist in the United States, for letting it continue to undercut the price of free labor, for letting a criminal justice system stick around to the point that it decays into being criminal itself, when there are clear alternatives that already exist. For throwing people convicted of the smallest crimes in with people convicted of the worst, and not caring about the result.
The system will take a while to change. Once the Bridewell House was built it was more than a hundred years before the justice system became reformed. But at the very least, we can remember the prisoners, and support them as they fight against the most odious aspect of this system.
The wardens want you to forget. Do not forget.