Bad economics and bad design being two completely different things and DLC commonly being a shoehorned in thing, not an actual additional feature to the game (unlocking items already on the disc compared to unlocking a new game mode or new mission) kind of puts the functionalist approach to game design in a bad position. Too much external pressure involved in the system.
But sure, they are good at marketting it, doesn't mean it is in the best interest of the game or the end user >_>
But anyway, this is all one more benefit to being absolutely terrible with money and not giving a fuck about it. I click the buy button and get things. Done.
Deleting CC info to have to rekey it is lololol. I have my CC details memorised from habit, so it isn't exactly a big barrier for entry.
That said, there is kinds of DLC that are good for games. Oddly in spite of being the poster child for terrible DLC (HORSE ARMOR!!!111), Bethesda properties are getting pretty decent DLC these days. Fallout 3 started to go in the right direction, giving new standalone missions that increased level cap and expanded on the things people enjoyed in the game (power gaming shit like weapons etc). They were even doing it pretty well in Oblivion at least with giving people what they wanted (more fancy housing... I mean it isn't for the DL, but for the target audience? shit was off the chain). Fallout NV DLC takes it a step further with level cap increases, new stuff and expanding of the setting and exploring subplots hinted at during the main game.
It ain't all bad.
Hell sometimes that kind of shitty DLC that gives you kind of trashy items for a slightly easier experience? If you price them low enough and they are clearly a minor opt in thing, set the price tag low enough and it is fine.
Also for what it is worth APB went belly up real fucking fast and is Free to Play now on a far more standard model.