Comment by Pannoniae

No it's not because it sucks the air out from the actual solution. ISPC more than a decade ago managed to demonstrate close-to-linear speedups for increasing vector sizes, even for branchy code.

Nowadays you can even get AI to write intristics and it works just fine, the portable libraries/autovec aren't really a serious player here.

Portability is also overstated - see the recent shift where Spotify decided to make native Android/iOS apps again instead of React Native. Usually, the number of relevant platforms is somewhere between 2 and 3, so portability concerns are more theoretical than real.