There's a certain amount of rose tinted glasses in that view. Sure, back in the "olden days" you just plopped in a CD and ran the game - but all the bugs in that game would never be fixed, and the contents it had were what you got. Those DLC mechanics that the game "was supposed to have in the first place"? Probably would never have existed back then. Unless you bought the "expansion pack"...
Besides, games are far larger and more complex beings these days. Yes, there are more bugs. No, the relative amount of bugs per content likely have not changed all that substantially. The thing is, those bugs have a chance to get fixed now.
Are there problems with DLC-mongering, unfinished games and cashgrabs? Sure, of course there are. But we're still in a far better place right now than we were "back then". The amount of games is much higher as well, as is their overall quality. So there are more than enough games which are made finished or patched for free.