My friends and I have a theory
that jewel cases
are purposely designed badly
to make music consumers have to fork out even more cash
The design errors you note are so blatantly obvious that they must have been put there on purpose. It costs a few UK pounds/US dollars for a set of 5 replacement jewel cases - and I find I always need some spare for ones that accidentally get broken. This is clearly a conspiracy - no one could design something so badly.
I store my CDs carefully and yet the central teeth that hold the CD in place seem to get broken very often. How this happens I don't know. I just pick up a case and hear that familiar rattle. I think it might be connected to lending out my CDs. :)
I find the teeth on the double CD cases is actually stronger. The bad design of the inlay booklet holder is also extremely irritating. If the artist tries to have anything more than a couple of pages, it inevitably gets ripped to shreds over time.
I am one of those people who, even if I own songs on MP3, like to own albums I like for the collection factor - the joy of owning the product itself. The crap design of jewel cases only serves to thwart my efforts.
The cardboard style of case, often used for limited editions, is, I believe, called a digipack. I hate these even more. Although they don't suffer from most of the plastic shattering faults of the jewel case, the fact they are cardboard means they get shredded very quickly themselves, just from general handling. They are also not liquid resistant.
see also Ben Elton's The Ministry of Crap Design