Ignoring the lack of updates if the game is buggy, games back then were also more focused on quality and make gamers replay the game with unlockable features based on skills, not money. I can't count the number of times I played Metal Gear Solid games over and over to unlock new features playing the hardest difficulty and with handicap features, and also to find Easter eggs. Speaking of Easter eggs, you'd lose a number of hours exploring every nook and cranny finding them!
Game updates bring bad with the good, because devs often rely on them to deliver a full, playable game.
When you bought a game back in the day, you got a full, playable game on the media. It wasn't always bug-free, because... you know... it's software, but they had to at least quash all the showstoppers without the benefit of a Day 1 patch.
And don't get me started about DRM...
They were also much simpler and smaller back then with often extremely limited specification variations. And DRM existed back then too, with some fairly egregious and infamous physical DRM checks.