There are still hardware differences today, but at least C and C++ have standardised memory-models (regarding concurrency) now. It's at least possible to reason

There are still hardware differences today, but at least C and C++ have standardised memory-models (regarding concurrency) now. It's at least possible to reason about concurrency in a hardware-independent way, and to write portable concurrent C, even if it's still nightmarishly error-prone to do low-level concurrent programming.