This is a ww2 flight game, how many peeps are even interested in ww2 planes, not many.
The games and internet can only handle so many peeps in a game, at a time. MMORPG games are written with specific criteria, some go for players over graphics, others go for better grahpics but have to limit players.
ie IL-2 has better graphics and effects, but servers only handle 30 - 50 players. AH went for players and not graphics, hence they have arenas that can have 400 -600 players.
If there was a real market for our type of game, new ones would be written to work with the modern hardware innovations. Just not enough demand, AH code was written a long time ago and is updated keeping older hardware considerations in mind, adapting to the current player base.
The late war arena usually has 350+ in it, what more do you want? You cannot fight more than 1 at a time.......................