People don’t play ladder because there is a fundamental dissonance between what the game is marketed as and what the game is.
The reality of FAF is that it is an economy centered tactics game. The tactics don’t matter unless you can do the economy because the game is built on soft counters rather than hard counters for the most part. A guy with better macro will beat you if he just dumps mass into garbage as long as he has 2.5x the mass in it.
So that reality makes teamgames that drastically simplify the eco situation much more popular. It isn’t really fun to go into the big robot epic nuke wars and explosions RTS and be irrelevant min 8 during end of t1 phase because you don’t know the efficiency of map control in scaling compared to any other method.
As long as the big marketing aspect of FAF is big boom robots and epic explosions, the game will inevitably be attracting people to the game modes that let you attain either.