Drummers do tend to be good drum programmers, but I believe they're a small fraction of the pool of pros. The drum machine made percussion feasible for lots of people living in dense housing for whom real drums were out of the question. (Also drummers tend to dislike using drum machines, because the real thing is more expressive.)

AI will be similar -- it will not just give more tools to people already in a given field (programming, writing, whatever), but also bring new people in, and also create new fields. (I personally can't wait for the gardening of AI art to catch on. It'll be so weird[1].)

[1] https://www.youtube.com/watch?v=MwtVkPKx3RA