They have a few other similar games that uses the same tech and feel to them (Tanks instead of ships), but your point stands (and they are all F2P AFAIK, same formula).

I've had a insight as to what you're suspecting (for another similar game), and I can say that it is definitely something like the top 1% that generate most of the revenue, and the rest of the 99% serve as kind of an AI for them to dominate.