And you know this of course because you were told what the numbers were by those who ran fighter ace and you've been told what the numbers in Aces High by HiTech.
We're not talking active subs, we're talking active players. I'm sure we would all agree that having 10k subs means nothing to gameplay if no one logs on to play.
I know the numbers because I play most days of the week and have for the last 15 months. FA had ~200-300 in Territorial Combat (their version of the MA), with another 100-200 in the Arcade Arenas most every night. To be clear, those were week nights.
AH is lucky to break 300 players on a weekend now across all arenas. Last Friday there were just at 300 players on, including for the FSO, AvA, and EW/MW arenas.
This past weekend was rather dismal, and I couldn't believe how few players there were online. A big contributor to this was the Bishop's HQ being down, and then the lopsided teams where Bishops had lost half of their bases, but neither the Rooks nor the Knights were capturing each other's fields. Bishops literally had less than half of the Knight's numbers for 3+ hours, and the Knights ENY was insanely high (to the point the musketeers were flying LA-5's - that's how bad it was).
All of the suggestions thus far are the same solution with slightly different tweaks. My suggestion was simply to try another approach that has been known to work in similar games.