AVX-512 one major problem and a bunch of minor ones. The major problem is that most computers still don't have it. Intel tried to segment their lineup and only put AVX-512 in their high end server CPUs for the first 2 generations that had it, but as a result normal programmers didn't have access to it, compiler devs didn't have access to it, and users didn't have access to it. As a result, most compilers don't do a good job generating AVX-512 code, and most programmers think AVX-512 isn't useful.

AVX-512 is great. The new instructions are incredibly useful for a wide variety of applications, but the fragmentation and segmentation by Intel has made it a total mess.