Long before I was a flight simmer, I was a board/miniatures wargamer. Wargamers were already a small, niche market, but I think I am among the last generation of people that would play and collect them. It isn't so much about the marketing. It is the culture. Combat flight sims are going the way of the old wargames. My son, despite being raised with toy planes, flight sims, and even RC helos and drones simply has no interest in any of these things. He has built a couple of snap tight models, but never a single glue and paint model. He is going into the 6th grade. I built my first model, an MPC 1/72 B-17, in the first grade without one bit of help from my parents. At about 3 years old, he could shoot down an Aces High AI B-24 with a Sptfire. There is nothing Aces High can do to attract my son's attention despite the fact that he could quickly develop his skills high enough to beat me. There is some hope. There are some teens that have adopted their fathers' flight sim hobby. But they are a very small group compared to all the kids playing phone/tablet/console games. I feel like I am among the last of the dinosaurs, dying out as mammals adapt to the new environment.
I want to see Aces High stay around indefinitely, constantly improving and expanding. But a quick reality check shows how long it has taken to upgrade the basic planeset, much less expand and improve the game. I was looking forward to the tour of duty concept with historical missions with historical numbers using AI to fill in the gaps... but all that came of that effort was the offline mission editor and if you look at the forums for staged missions, you will find they are pretty much dead. Strangely enough, Warbirds is somehow still up and running despite miniscule numbers of paying customers. I wonder how that is given that Aces High is a much superior revision and has had much better player numbers for years?
The only thing that can really be done to improve numbers is word of mouth. Try to get friends and family involved in flight sims of any kind and give them a taste of Aces High as soon as they have the hardware to try offline and free gameplay. In all my years of PC flight simming, I can't recall successfully recruiting even one person over the long haul. I have currently impressed several visitors with my VR/home cockpit setup. But none of them are going to go home and throw $1,500-$2,000 into a gaming PC, another $200 to $1,000 in USB controls, and another $400 into a VR headset.
I do have one neighbor that is as much a flight sim fanatic as me and he even has a real pilot license. But he only flies FSX and prefers to fly airliners. He recently posted on our neighborhood's facebook group about the quality of his setup and that he was willing to give kids time on his system and even give free flying lessons. He got only one response from a teen. So, I suspect growth in numbers is unrealistic. We will be lucky if we can keep the number of people interested in flight sims stable at its current level.