> With multiple layers of caching and nearly a couple hundred registers in current CPUs this is far from the truth.

Add to that the aggressive optimisations performed by modern compilers and that mental model breaks completely. It may be a good conceptual model, but it's not the model under which your program actually executes.

However, even programming in assembly keeps you very "far from the truth", since modern CPUs are very complex beasts internally and that complexity is mostly not visible in the ISA.