The majority of updates are bugfixes or maybe new content for fairly new games, or "in-game purchase" stuff that is just extra content. I don't consider extra content to be a part of the main game. I pop in and play a ton of PS games....Assassin's Creed, God Of War, Infamous, Uncharted, Dead Island...
While you can buy other stuff, and play online, you most definitely can just pop the disc in and play. I've only recently had internet even connected to my PS, and for the last couple decades, all I ever did was just buy games, pop them in, and play.
I recently started downloading content on the PS store, but what I've downloaded were all completed games. No in-game purchases...no new updates...just finished product.