>fails to demonstrate how code-tests result in objectively better code.

Tests give the freedom to refactor which results in better code.

>So, testing has its place, but testing is really no better than simulation

Testing IS simulation and simulation IS testing.

>And in simulation, the outputs are only as good as the inputs. It cannot guarantee code safety

Only juniors think that you can get guarantees of code safety. Seniors look for ways to de-risk code, knowing that you're always trending towards a minima.

One of the key skills in testing is defining good, realistic inputs.