Well advertising it wouldnt be easy. I think that this game doesnt have enough publicity, maybe if they shocasted it in a irl event or something like that...

Instead of the launcher what could be made is an interface in-game similar to what Cs:go has. There when you open the game you would be connected to the forums through that ingame browser, that way more ppl would check them and so there would be more active members. Also I doubt that Tb's updates ever match the weight of War thunder's but yeah that would be a bit annoying