I don't think the issue is using declarative UI frameworks, it's that the rendering engines these frameworks are outputting to are not taking accessibility into account.
Totally. I had a colleague who was a pretty awesome programmer and was completely blind. When I first met him, he was working on a braille 3270 terminal. Those IBM terminals were capable of all sorts of stuff.
Clearly no one put thought into any of that. It was just “make terminal, but pretty”.