You have no idea how many developers would give an arm for population as big and as stable as the one CoH2 has.
It might not be competitive MOBA or FPS level, but for its genre its pretty damn huge.
Just look at the market, every other RTS game that isn't SC2 is dead within 6 months of release.
CoH2 STILL keeps the 8-10 concurrent users after few years. Even SC2 is on a slide down and CoH is stable.
Yes, I'm actually still surprised after all this time CoH2 still manages to retain about 3000+ to 7000+ players. Even a long time after (what I assume to be is) CoH2's last expansion.
There's still that charm in a WWII isometric game that CoH2 fulfills so nicely.