[chongli]

Your argument boils down to this: because we cannot look at an operator and have a 100% iron-clad guarantee of the exact sequence of instructions the compiler will ultimately emit, we should throw it all away and just settle for every operator in the language potentially being a function call that might be O(1) or O(n) or even O(2^n). That's called throwing out the baby with the bathwater.

every single person that is good at micro-optimizations look at the compiled binary as a first step

That isn't an option when you're writing portable code that runs on many different platforms, some of which may not even exist at the time you're writing it. Furthermore, micro-optimization isn't the only reason operator overloading is bad. The implicit flow control dramatically inflates the search space for what every single operation can do, making all code much more complicated to inspect at a glance. This carries over to debugging, where stepping through code is much more cumbersome when each operation can involve large amounts of indirection.