^because the way you want to play the game destroys the game for everyone who does not want to fly.
Also, OT: I've had all professions maxed on my alts for the last two expansions and still bought stuff from the Auction House because i was too lazy. And you can be sure that many other people will feel the same. I think you are grossly over-estimating the impact profession building in garrisons will have on the economy.