Think of slowly sipping whiskey. Now think of drowning in beer while doing so.
The problem with boilermakers is that the whiskey stays in the shot glass. So you have a nice glass of beer, then, as you get to the end, you tip the glass far enough that the shot glass pours out. Now you have to sip whiskey mixed with beer. Sure, that might not be so bad if you're in your Carlsberg Years, but if you're a Blue Light-swilling fratboy that's the last thing you want to be tasting (well, not the last, but it's pretty bad).
A much better plan is just pour the whiskey in. Or, if you want the boilermaker experience without getting your shot glass wet, you can drink a bottle of beer, then pour yourself a shot glass of whiskey and drink that. It's basically the same, trust me.
This has been a Noding While Drunk production.