But what is the basis for postulating that? You're kind of ignoring a century of experimental particle physics when you ask that question. Nothing we have so far observed would lead us to believe that's true. In fact, its' quite the opposite. We see that decohered quantum systems behave completely classically! This is what the Newtonian limit really describes at the end of the day.
Discussion
Also, after thinking more about what you said at the very end there, I'm very confused about what you're hypothesizing here.
We can experimentally observe coherent quantum systems. That's what quantum entanglement is. These system are, by their very definition, not collapsing spontaneously every unit of Plank time. Also, nobody believes the wave function evolves in units of Planck time, in a tick-tock way. This is a very very big misunderstanding of what the Planck time actually is. The Planck scale *is* the Newtonian limit. It's the point at which quantum gravity becomes important. Which we notably do not have a working physical theory for, hence all the String Theory and Quantum Loop Gravity stuff that you periodically hear about.
This is just a long way of saying that I'm actually really confused as to what you're actually saying, here.