For people mentioning nostalgia - for me at least it is not that.
The main thing is that top tier games used to be challenging. This is what attracted a lot of people to gaming in the first place, ability to compete with other people in a non violent, non physical way. The ultimate test of wits and skill.
That's why games like TMNT were so popular, it was a great game, with awesome graphics, with a very popular brand tie in, while at the same time being extremely challenging. In my area there were only 2 kids who were able to complete the game.
Tekken is the perfect example of a game that completely lost it's mojo: we went from a fast arcade fighter, that had graphics that were second to none on the platform of choice, and still had no easy mode for casuals, which allowed good players to stand out and feel special.
Tekken 7 is a garbage game - it's slower, with terrible graphics and special moves. Since Tekken 6 Namco is doing everything they can to kill the franchise.
Racing games are another example, Gran Turismo had it's soul marrying simulation and arcade to create a unique, challenging experience. Right now they aim for "simulation" with assists, that makes it feel like every other game of the same kind - bland.
As far as arcade racers are concerned, the genre is dead. Pretty much all of the arcade genres are dead - have you played Ace Combat 7? It's hot, boring garbage.
RPGs have also been simplified to the point of making you feel like an absolute idiot, and the only challenge stemming from the time needed to check every corner of the map.
The only refuge is indie games - but they usually have terrible graphics. In the recent years, the only games that actually felt like good games to me were Bloodborne and Monster Hunter World.