Sure there are. The problem is that they're mostly playing World of Planes/Tanks/Ships or WarBlunder. Even worse is that they think those games are good.
and im going to make a wild guess that having large amounts of free content gives them a large advantage in numbers.and they probably do a decent job of converting free players to paid players.(i mean they keep making them, adding stuff to them, and the forums are active)
and they have modes (if not the entire games) to cater to the lowest possible denominator.
so kids and noobs have a chance.
Aces high has some of the absolute best large scale air combat for sim type flyers. and it has a lot going for it once you are proficient.
but there is a huge learning curve, and it feels dated. there is a very slim chance your average high schooler is even going to give aces high a serious look.
to most young people its going to feel horribly outdated to begin with, add in the 15$ a month subscription (How many subscription based MMOS are still around, 1,2? WOW and Final Fantasy maybe, though WOW lets you earn free time.)
and sure you may no want a bunch of youngins runnin around, but there are only so many old retired flight sim guys available.
no one may like the idea, but everyone seems to disregard the people who play those types of games. or fortnight or call of duty.
however that is where the new blood is, and what you have to compete with.
the trick would be to entice them without ruining the core game