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!
I do go without. The only time I ever play online is playing PvE games with my good IRL friends that live in different countries and states now, and that's maybe twice a month.
No randoms, no tantrums when we make noob mistakes, no toxicity. When my friends aren't around, I play single player games or play with bots instead of people. I highly recommend it.