Lock free code indeed does indeed need to rely on memory model. Relying on underlying machine model is not fooling oneself.

Please don't conflate visibility with load/store order. It's a different matter.

See how C++ memory model operations map to different processors, especially how many cases are simple loads or stores on x86.

https://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html (link from another comment in this discussion)