you don't need to know electrical engineering to design an airplane control panel
lol, of course you do. and A LOT more. Hence it's usually done by a team of experts. Pilots, eengineers, manufacturing, regulation/standards, safety,...
UX is just one of many parts of the expertise needed. same in software.
What you're claiming is wishful thinking that has nothing to do with real world workflows. I also don't know a single UI designer having the troubles you are pointing out.
The majority of designers (not all) I have worked with have been very shy about technical work, so having no clear "non-technical" contribution pathway is a deterent.
That's the difference between designer and UI Designer. Just because you can draw an UI with your favourite tool, doesn't make you an UI design expert.