Aces High is over 25 years old AHIII is over 10 years old for a subscription based MMO WWII combat flight sim that is pretty damn good!
Air warrior the grand daddy of the genre lasted just over 13 years through several versions (DOS, Win, II, III, MV) and across several services (GEnie, Dephi, Compuserve, AOL, Gamestorm, EA).
The only major competitors to Aces High III is Warbirds26, WWIIoneline, World of War Planes, and Warthunder. Warbirds has become a dead rotting corpse of a joke game, WWII online isn't much better, World of Warplanes and Warthunder are both arcadey free to play services.
Il2 is somewhat of a competitor but is more limited (No PTO), It's more of a single player game, has a steeper learning curve, is self hosting (Limited Player Count), has a different business model (Not subscription based) Requires a beefier system specially VR.
DCS is about the same with an even steeper learning curve ... This is study level, basically MSFS/Xplane with guns It does everything from wwII to Late Cold War/Early modern. (They are getting the F35). It requires a monster system their WWII is limited but does do PTO with the Hellcat and Zero Coming in 2 weeks (That's a Sarcastic Joke).
Aces High III biggest strengths that it has right now is that no one does VR better and it Doesn't require a beast of a machine to run even in VR; I ran it on a 4th gen intel xeon (I7 4790 class) 1080ti and valve index no problem). Something people don't notice is No one can do WWII Scenarios like Aces High. AHIII can handle bigger player counts with less resources and AHIII has the biggest WWII Plane set and we have Ships Boats and Ground Vehicles.
You really don't want to talk about the system you need for DCS specially in VR let alone the cost.
I have a 5900x, 64gb DDR4, Gen 4 SSD and a 3080 with a valve index. I have to turn my graphics settings way down to get 30-45 FPS in VR. My new system is a 9950x3d, 96gb ddr5, gen ssd, and a 5080. I purchased my Memory for about $320 USD last I checked it was selling for over $1500. unfortunately I can't fly right now and have not been able to since June of last year due to an injury.
The only thing DCS completes with AHIII for is for the player's time but it's the Same with Grandkids and many of us are at the age.
Aces High Biggest weakness is Stale Game play (Dear Brook we need more Scenerios

) for a subscription service (Just to be fair anything can get stale over time even fun time with a hot hooker willing to do dressup and roll play) and its graphics are dated which is why it can't catch the Warthunder kids on their way to another pretty game or a Study Level but to be honest DCS players make fun of Warthunder players when they first come over ... It's like seeing the face on an Army recruit when they first get to basic and learn the meaning of the term "Shock Treatment".
Expecting HiTech to overhaul the game at this time is unreasonable. He is basically a one man indy developer and he's older than me .... I'm retiring in like 7 years. Hitech has a family. The most we can hopefully expect is maybe a lower subscription fee/tier or possible a free or poor mans subscription. I think he should consider selling scenarios and special events to non subscribers; Brook and His crew work is at least worth $10-20 per scenario.
I believe Hitech will at least keep the game going for as long as he can afford to keep the lights on and have change enough for a good bottle of single malt scotch. We should have at least a few years. I'm mostly concerned with what he does when he feels it time for the game to fly west.
But again Aces High and DCS only compete for the players time and many people don't have time to spend 25 minutes just getting their airplane started. Even if they where competing for the players dollar most don't have the money in current times for a $5,000+ gaming rig capable of running the game in a state that it looks really good specially in VR.
Gameranx ranked DCS as THEE MOST DIFFICULT Game For NEW PLAYERS (Pay close attention to what he says about time, I had to actually watch a WWII P51 training video to learn how to start up the mustang in DCS.) Basically think of it as the Dark Souls of Flight Sims.