Sorry, missed your reply at first.
Pathfinder itself is, imho, fully open to debate. We have to have -something- that does the reqs for getting flying whenever they decide it’s time to allow us.
… but the requirements themselves aren’t hardcoded as part of that. Once upon a time it was money, then it became achievements (after all we had flying before we even had the achievement system).
There’s a balancing point in there though - where players should have done the content, quests, most of it… but the pt2 reqs… I think those are up for debate.