This reads to me as a cogent defense of one particular interpretation: Everett.

All is clear and logical except the part where Aaronson endorses the opinion that Everett isn’t wrong, but grandiose (whatever this means). In justification, it seems he is pushed into further twisted locutions. He speaks of what “breathes fire” into branches of the wave function and says that the question of existence of other branches is “above the pay grade of physics”. Breathing fire and pay grade of physics?

How much simpler to just assert that yes evolution is unitary at all times and, yes, this implies many classical branches.