If UT3 was still considered "fun" and "the shit" or whatever there would be heaps of people playing it.
I don't think this has anything at all to do with cosnoles. Everyone loves to play that card but 90% of the time they misunderstand it. There's a much more diverse range of games out there now and UT did not evolve at all. People don't play it because it didn't change, they've already played it and newer games are much more approachable.
Why were Quake and UT so popular back then? I think because there were 2 well hyped games from a very very
short list of shooters and were the only 2 that had dedicated servers in an age of dialup - that meant they were the only games that were actually playable online (from their early versions) and thus maintained a community and a certain level of popularity, but once the shooter genre diversified and more and more types of games starting using dedicated servers and MMOs sprung up ect the players scattered across the inter webs.
There're so many new and interesting games around now I see no reason to go back to UT or Quake. I played those games 12 years ago, not keen to revisit it, just like I've moved on from Counter Strike and other games.
Even if VALVe released Counter Strike 2 tomorrow I probably wouldn't go back to it for long. I'd have a short fling, long enough to realize they really haven't changed the gameplay, because they can't, it's CS, everyone would kill them if they did even if they're sick of it already. Play it for one or two days then get bored because I've done it all before.
Counter Strike 2 would feel as bad as the latest Rambo movie, interesting but a dinosaur in makeup isn't really as cool as it sounds, just like the UT3 really.
Some people can play the same game endlessly, but I can't. Too much other stuff around to try out.