"One piece is that forget that what we're trying to optimize is happiness, and if those 13.4% of waiters are happy, then who cares if they have a BA or MA?"

Sorry to nitpick, but this is important. Never mind whether a degree really brings more happiness - who said we're trying to optimize happiness anyway? It's certainly not what most societies try and optimize, at least not on the societal level.

Just as a simple example, sending kids to join the army is not in the best interests of the kids' happiness, nor in the best interests of the parents' happiness; yet every society chooses to do so (never mind your personal stance on the military, societies are obviously optimizing for self-preservation over the happiness of individuals.)