It's really not. As an example, for string processing tasks (including codecs which various server software spends a significant percentage of its runtime on), NEON includes a deinterleaving load into 4 registers and byte-wise shuffles that accept 2, 3, or 4 registers worth of lookup table. These primitives are quite different from those available on AVX2 or AVX-512, and the fact that they are available and cheap to use means you end up with somewhat different algorithms for the two types of targets. Even the practice of using the toys available in AVX2 well for this sort of task is somewhat obscure. Folks who have worked on codec-type stuff but primarily used AVX-512 often have trouble figuring out how to do most of the same things in similar instruction counts if masked versions of the instructions are not available.