I proposed a similar idea a while back. The factories are not necessarily Buff targets. Hell, Jabo's do the job of Buffs now anyway. So let's not make this another Buff Vs. Fighter thread.
The idea is to add challenge to the game. Karnak complains that this violates a persons right to fly what they want. Pick some of the other online games out there. You don't get everything you want, all the time. That's the challenge for a person to overcome. I used to play Ultima Online. I like a certain type of armor. If I got Killed, lost my armor, and did not have the money to purchase a replacement, guess what....I did not get that armor. I used something else. I was forced to adapt. It made the game that much more interesting.
So let's say there are 12 factories per country. Now, one gets bombed...A random vehicle (Fighter, Bomber, GV) is taken out of the set for 30 minutes.
Is it so tragic if Lazs loses his FM2 for 30 minutes? (Not singling you out Lazs, just an example.) The FM2 is my ride of choice now as well. WHat would I do? Go to the F4F, or the F6F.
Regardless, it allows you the chance for some diversity in the game.
This is not an idea for Buffs. This is an idea for everyone seeking a little more of a challenge.