I checked the 2142 servers and there were only 7 populated servers I looked at the Battlefield 1942 servers and there were 8 with more than 2 people. Where did all the people who played 2142 go?
Well BF2142 never had as strong a playerbase as BF2 even when it first came out (the scifi theme was less mainstream I guess), so it is only to be expected that the BF2142 playerbase would fizzle out before the stronger BF2 one, especially with a much more prevalent modding community for BF2. I sometimes think we did shoot ourselves in the foot a bit switching from BF2 to BF2142 to mod for, but there were tools and features in BF2142 which were beneficial to us, but we did then leave ourselves with a much smaller potential playerbase unfortunately.
And I always bring this up, but everything points to EA/DICE intentionally killing the game when it was clear the 2142 playerbase wasn't big enough for them.