Come on trav, you've been around a while, you know better than this.
Perk values are currently assigned to planes and vehicles whose merits lie in high individual performance. Why award perks on a team-based system just so that awardees can spend them on individually-focused crafts? It is a diametric opposition that is inherently illogical.
If your system was implemented, we'd have to instead perk great "team" planes and vehicles...110G's for town killing, m3's for troops and supplies.
And of course on top of all of that, some of us don't care about winning the war, some of us do, but the common denominator is that we all play an individual role in whatever it is we do (impossible not to, unless you play this game through some sort of spiritual sharing proxy). Therefore perks are awarded for individual performances because we all deserve to acquire them, and individual performance is the only common denominator we are all guaranteed to share.