I specialise in video (ffmpeg and webrtc, in essence - on the level of "build me a demuxer for format ffmpeg does not yet support" or "build me a from-scratch C++ implementation of webrtc endpoint tailored for a particular narrow use case").

This involves a lot of "C-family languages", reading and understanding RFCs, and other "hard" skills that are not passing fads at all.

And i can tell that the market has become terrible, and it is the same for some colleagues of mine with less narrow specialisation. I stopped looking for contracts: it just can't work now, i need to wait.

As for lack of business domain expertise, well that's spot on. I barely seen/participated in any actual working businesses in my life, probably because i never held a full time job in my 25 years of career, and i'm in Europe where it probably doesn't make sense doing anything (or at least i haven't seen anyone succeeding), so i'm stuck being an "offshore outsourcer" for Americans.