> Classical mechanics is not something sacred. It is our first serious model of physics.

Just a sidenote: it is at most our second serious model. Aristotle's Physics has a bad rap, but it's "a correct and non-intuitive approximation of Newtonian physics in the suitable domain (motion in fluids), in the same technical sense in which Newton theory is an approximation of Einstein's theory". See "Aristotle's Physics: a Physicist's Look" by Carlo Rovelli (https://arxiv.org/abs/1312.4057).