Firstly, there are in fact a lot of problems that benefit from parallelization, but are not quite wide enough to justify dealing with (say) a GPU. For example,

Firstly, there are in fact a lot of problems that benefit from parallelization, but are not quite wide enough to justify dealing with (say) a GPU. For example, even in graphics you often have medium-sized rasterization tasks that are much more convenient to run on CPUs. Audio processing is similar. Often you have chunks of vectorizable work inter-mixed with CPU-friendly pointer chasing, and the ability to dispatch SIMD work within nanoseconds of SISD work is very helpful. Secondly, AVX-512 (and Arm's SVE) support predication and scatter/gather ops, both of which open the door to much more aggressive forms of automatic vectorization.