[ctdonath]

This is radiantly insightful. It makes perfect sense to me. The effect of reading it is like drinking a Pan Galactic Gargle Blaster: feeling like my brains were smashed out by a slice of lemon wrapped round a large gold brick.

Yes, in real physics solves vastly complex equations fast. That's not enough to discount the point here. There are limits on physics itself: the particles in a cat (presumably one owned by Schrodenger) are so numerous that for all of them to express, within a reasonable time, superpositioning the effects of a single radioactive atom's unobserved state would require particle interactions occur way faster than Planck time.

Nothing moves faster than light. There are a finite, albeit large, number of particles in the universe. Nothing can be smaller than Planck length, and no particle interaction can occur faster than the time light takes to move one such unit. Upshot: macroscopic superpositionining effects cannot occur because it takes too long for full propagation among particles numbering on the magnitude of Avagadro's number.

There's an upper limit to what can happen, because there's only so much stuff and "happen" can only be so fast.