While there are still good games being made, pretty much all the genres have stagnated or are being "streamlined" (cool unique and unusual shit removed in favor of more samey, down-cut standardness). The best stuff is just a throwback to the good old days: retro shooters like Dusk, Ion Fury, Amid Evil. They're essentially doing what Quake and Unreal did 20 years ago. They're good at doing that, sure, but they're not adding many new things to the formula.
RPGs are in a similar state. Larger budget titles that end up at least decent are just throwbacks trying to capture the good old days of roughly 1995-2005. Anything Obsidian and inXile does is just an attempt to make a game that is like the classics: Wasteland 2, Torment Numanuma, Pillars, etc etc. Even Outer Worlds was just an attempt to repeat New Vegas, a now 10-year-old game that became a hit due to great quest design and exploration, and despite its shit engine.
With all these games trying to ape the classics, it's natural that we no longer get classics. How many of the classics - both our beloved Codex classics and also games considered classics by the mainstream - just tried to ape other popular titles? Almost none of them. They all did their own unique thing and that was how they became classics.
Baldur's Gate? Big D&D adventure using an RTS engine, made RTwP popular which wasn't a common combat system before. I'm not a fan of RTwP and find the setting to be very bland (especially compared to BG2) but you can't deny that it was innovative.
Diablo? Greatly inspired by roguelikes but combined the formula with real time action gameplay. Had hundreds of copycats. Diablo 2 is by many considered to be the peak of the genre. Pretty much every clone that followed just copied the formula and hoped to reach the same success, while not really changing anything about the approach to gameplay.
Fallout? Revolutonized RPGs with its approach to non-linearity. Turned choices and consequences into a relevant thing.
Half Life? Revolutionized the FPS genre with a more story-centered approach and a coherent world that feels like a real location rather than jumping from disconnected level to disconnected level. It changed the genre for the worse IMO but it's undeniable that it stuck out from the competition back in the day.
Troika's games. All of them. Arcanum, ToEE, Bloodlines. Each takes a different approach to game design, a different focus, and while ToEE is the most traditional of them all it takes a fresh approach to D&D implementation on the PC (gridless movement rather than rigid squares or hexes). Arcanum is Fallout on steroids but different enough to not be a simple attempt at cloning previous successes, Bloodlines is a unique urban fantasy first person RPG and we haven't seen any clones of this up to now.
It's not even about being a milestone in the history of game development. It's just the simple fact that these games tried new things, were okay with taking risks by breaking the mold, weren't afraid of sticking out from the competition by being different. They had an identity. They had a soul.
Today, a lot of games lack that identity. They don't want to stick out from the mass, they want to be indistinguishable from the mass, especially big budget mainstream titles. You don't wanna be too different, oh no, that might put off the consumer who expects certain conventions. And conventions are everywhere, like they're set in stone. And nowadays every Joe and Jill has a Titter and a Fagbook and pesters devs with inane requests. "Please, can we have crafting in this game? All the games I like have crafting so I absolutely NEED crafting in my game or I won't buy. Thanks." And the devs - and especially the publishers - listen to that kind of drivel, and so certain features become convention and turn up in every single game on the market, no matter if the feature actually contributes anything to the gameplay or not.
In the past, we've had games that broke conventions or made changes to the core systems of the genre. The Elder Scrolls games used to have plenty more equipment slots than most other RPGs, making for some nice dressup and item hunting. Nowadays they have the same amount of equipment slots as every single other RPG currently on the market. Helmet, gauntlets, weapon, shield, armor, boots, that's it. Every RPG has the same amount of slots. Most mainstream FPS games limit the amount of weapons you can carry to 2 or 3. Why? Originally it was introduced by Halo because console controllers are worse at weapon selection than PC keyboards, but nowadays it has just become a convention. It's done because that's how everyone does it.
There's such a blind following of convention among big budget games, but it also bleeds down into indie games. We rarely get games that try to innovate, try to do something truly different and unique. Whatever you may think about Disco Elysium, the main reason it became so popular with many people is that it was a breath of fresh air. These devs didn't give a single shit about convention. They went all out and made their own thing and the end result is a game with a distinct identity, a game with a soul.