Its so easy to forget all the garbage games that got churned out 20 years ago. Even the good games - your FF7s and Warcraft 2s - had their share of notorious glitches.
The ability to patch a game after release has definitely not improved first-iteration releases. But you can go out and get a copy of Skyrim or Resident Evil 7 or Dragon Quest 9 and play it with a very reasonable degree of confidence that it will work end-to-end as intended. You can’t say the same thing about Super Mario 64 or Mortal Kombat 3. Hell, the whole speedrunning community has to distinguish between “glitched” and “glitchless” runs, precisely because finding glitches in classic games is such a pivotal part of beating them in record times.