I'm not sure how you quantify "very small" here? I'm running low-level conferences [0] and they're big enough for me to be a full-time organizer for them: with a job fair that's included Mozilla, real estate, nuclear defense and various game studios.
We could check popular job boards (or HN's Who's Hiring threads) and see how many postings mention compilers, kernels, assembly, GPU, etc. Then compare that number to the total.
Did the number of jobs of people coding in assembly go down, or is it that the number of jobs of people not coding in assembly go up? (I truly don't know. Just curious)
I tend to believe that the number of people working with machine instructions might have even increased! We have much more of the tech that I mentioned nowadays compared to 90s. Also a lot of other industries have entered digital age and in many of them, i.e aviation, transportation, financial, etc. knowing the intricacies of your hardware is crucial.
The thing is that web development has seen such a boom which has seemingly dwarfed everything else in its wake.
[0] https://handmadecities.com