In a no 9/11 world does cell shaded graphics become popular over realism by the latter half of the 7th Gen since for most games of TTL realistic FPS didn't really caught on and Inspired by the success of TF2 many franchises like Battlefield go into a more cartoony direction?
I think the opposite,the whole war on terror changed the setting to more grounded ones and based on 'real heroes ' , before,the most popular console fps were Golden eye, perfect dark (spy genre) and medal of honor (WW2), so more historical wars would be used,the same the spy thriller
I don't think either of those things would get butterflied away, quite the opposite. With no war in the middle east to remind people of the real cost, that genre could get even more popular. The plotlines wouldn't focus on the middle east so much but they would very much exist.
I wrote a quite long and detailed hot take about how Source Engine games and the whole Garry's Mod/TF2 memes subculture of the late 2000s and early 2010s YouTube would have been affected in a world with no 9/11, but the text is in my broken computer that is currently in repairs, so I will hit you guys up when I post it eventually, I will do the same with everyone that is interested in Half-Life 2, TF2, Gmod, Left 4 Dead, and all Source Games and Mods in general would look like in a world with no 9/11.
It has been quite a while that I do not delve into the making of TF2 IOTL, but from what I remember, a big inspiration for the present artstyle of the game was Pixar's The Incredibles from 2005, so it will depend whenever if Pixar still makes The Incredibles ITTL or not, this would perhaps dictate if the TF2 of OTL would be made or not, because TF2 underwent various drastic artstyle and gameplay changes throughout its 9-year development span (1998-2007).
Hell, in 1999,
TF2 was originally a realistic military simulation shooter!, then around 2001-2003 it became
a War of the Worlds-inspired steampunk & sci-fi alien invasion thing, and finally, around 2004-2005
it evolved into the cartoony team shooter that we all know and love, the realistic military sim TF2 from 1999 was truly ahead of its time, this was years before the War on Terror started, and thus influenced games such as Call of Duty 4, which made the whole "action-packed and patriotic military shooter where you kill terrorists in the Middle East" genre and gimmick the pop culture colossus of the late 2000s.
At least for me, unlike GTA 3 and Rockstar Games that make specific types of open-world urban crime games, Valve never struck me as a company whose games and development philosophy were that much affected by 9/11, if at all, if you read up information about their game development stages, the seeds for what would eventually become Half-Life 2, Team Fortress 2, and
even the Steam online digital game shop service were already planted as early as 1996 before even the first Half-Life game was released, and way before 9/11 happened.
So other than speculation used as an excuse to write fan-fiction for alternate Source Engine games and an alternate trajectory for Valve in the games industry, I doubt that Source Engine games and Valve Software would be that much different in a world where 9/11 never happened, the main thing that would change would have been of course fan-made mods, so for example, it is likely that the
Insurgency Mod, which later became the
Insurgency franchise, would likely not exist in a no-9/11 Timeline, and also, Middle Eastern/Arabian-themed maps and obvious Islamic terrorists would be way less prominent in Counter-Strike games and its custom fan-made content..
So I feel that thinking that Valve games would have been quite different from OTL, would be like being a DeviantArt artist from 2008 making alternate Source games just for the sake of fan-fiction and fanart fun, rather than it being based on anything about the actual development philosophy of Valve, like describing a Left 4 Dead equivalent where the enemies are aliens instead of zombies, the Engineer from TF2 being a smart and pretentious MIT scientist from Massachusetts instead of a traditional hillbilly/cowboy from Texas (due to the Texan G..W. Bush not being re-elected in 2004, or not being elected in 2000 in the first place), and Half-Life 3 actually releasing circa 2009-2011 because..... reasons.