Which games will be forgotten? The overwhelming majority of them. Which games from the early 2000s are still talked about now? There are some, but a lot more have been completely forgotten.

Erm, most games? You're better off asking which games people might remember 20 years from now. You ask me what games released in 2004 off the to of my head I could only remember Halo 2, Half-life 2 and Doom 3 (and this one I remember because of Half-life 2). I'm 100% certain I'm forgetting some huge release from 2004. But that's the thing, only the really memorable games will be remembered.

I could probably mention 20-30 games from the 00s (maybe 50-60 because some series released a lot of games in that time frame. For example Half-life 2, episode 1 and episode 2 make up 3 games, but I remember all of them because of Half-life 2), but over a decade thousands of games were released. The vast majority of games will be forgotten.

20 years from now maybe some old man like myself remembers Space Marine 2, but it will get wiped from the collective memory.

Wishful thinking? Fortnite. Pleeeeeease let's forget about Fortnite.

The decade is not even half over yet...

But so far, from what I have heard, I would place 99% of Nintendo's eShop in that category

Live Service games. They'll be shut down, inaccessible, and forgotten.

Think like Tabula Rasa from 2007. Shut down in 2009. Poof! Gone!

https://en.m.wikipedia.org/wiki/Tabula_Rasa_(video_game)

Concord

Starfield. It's sooooooooo bland

Unfortunately, Wizard of Legend 2 when it releases will.probably be forgotten if the beta is anything to go off of. Other forgettable mentions:
WH40k: Dark Tide
Nessiu
Kill the Justice League
WH40k: Rogue Trader (rip cause BO3 dominated it)
Astroneer (not sure if this is a 2020- release)
Friends vs Friends (sad cause its bomb but dead)