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 am in full agreement with this statement, and would like to add that I think that older games often have a much greater artistic value. They were concerned with crafting an intricate plot, super immersive environments, powerful and transformative music, memorable characters, etc. One game where in my opinion you really feel the volume of love and artistic expression as well as perfectionism put in is the first Risen, and it's fairly obscure, but I find it to be so captivating that I'd easily play it with greater enthusiasm than any new Ubisoft copy-and-paste title or Valorant / Overwatch / CS:GO. Still, I think that this art / passion approach of quantifying a game's "goodness" produces just as many contemporary candidates for great games, like The Witcher 3, Baldur's Gate 3 or Red Dead Redemption 2. The things I like about old RPGs / adventure games are probably not specific to the past, but instead heavily developer dependent. Developers that love their work and are given enough time and money will produce great works of art in the same way that they have 20 years ago.