No, I'm actually saying that everything is QM, and yet for some phenomena you can use instead of that some effective theories called classical physics, that hav

No, I'm actually saying that everything is QM, and yet for some phenomena you can use instead of that some effective theories called classical physics, that have these nice properties of needing just calculus and vector analysis and being easy to draw. That, and they having been discovered before more explanatory theories make them very popular, but it doesn't mean the world is actually separated in domains. Usually physics is taught in terms of micro and macro descriptions, the macro applies to those situations likely to be adequately characterized by classical physics, but that's because Planck's constant is really small, not because there's such a thing as a classical world. Hence for macroscopical everyday stuff classical physics usually works reasonably well, but even there, right in front of you there are very obvious phenomena that can't be explained with classical physics. About the pilot wave theory, well it came after the standard formulation of QM, so people didn't choose between them, and it's quite a patchwork that brings its own complications. Apparently as it includes classical trajectories some people love it, ignoring that you put by hand the actual QM wavefunction to make it work, then you fix things to get the old stuff back. I find all that weirder than standard QM.