Right now Im in lobby and there was 1 game with WK in name before, but now none of the 20~ joinable games seem to say WK, does this mean no1 uses expansions?

The "Details" column on the right shows which patch and which mod is used. For WK games it will say "v 1.5 Beta R7 | WololoKingdoms". The game room title can be freely chosen and doesn't have to have "WK" in it.

Not everyone plays WK, especially in the NPL, but even there it should be at least 40% or so.