It's still possible to incorrectly use relaxed operations, and have your algorithm only incidentally work because the compiler hasn't reordered them and you're

It's still possible to incorrectly use relaxed operations, and have your algorithm only incidentally work because the compiler hasn't reordered them and you're on a CPU with a stronger memory model. But yes, it's an order of magnitude easier to get portability right using the C++/Rust memory model than what came before.