I see that accurate simulations are taking a backseat to the eye-candy and instant gratification type games. Aces High provides a player with little eye-candy, but great challenges, because the flight physics are high, and are challenging, and require an individual to actually learn something about flight, and flying, versus learning how to use macros and cheat codes on a controller.
The crowd for more accurate sims has always been noticabley smaller than the more arcadish flavours, for obvious reasons. AH, however, has a few cornerstones to its gameplay which further discourage new players. Examples include the perk system which functions solely as a seal clubbing tool, allowing veternam players to maintain an added advantage, ad infinitum, over new players. Massive maps that make for desolate enviroments under current population numbers in a persistant game world also prove less than inviting (compared to the 15 minute game windows which insure instant action in games like WoA or WT).
Then you've got the added eye candy in these other sims, ease of entry into the games, ability to "purchase" balancing equipment (unlike perks in AH which insure the new player can never be on par), all add up to a model that is more inviting, and certainly more profitable.
I don't recall the exact number, but I believe WoT did somewhere around 300 million in revenue last year. I wouldn't be too critical of the Russian's, they're kicking the rest of the worlds bellybutton in this game space.