I think the answer was system requirements.
Each skin takes a certain amount of memory....
For instance, let's say 200kB (although I think they may be closer to 300kB).
15 skins max = 3MB per plane type of skins, x >75 Planes/Models = > 225MB of memory required, just for the skins... that's not including models, terrain, terrain textures, ship textures, special effects, the simulation information, network, etc, etc etc.
In a game that's strived to keep system requirements fairly low, that's a decent chunk of resources to give up right away.
