I don't think that was entirely missed: AFAICR, I pointed out somewhere that in that case, it's up to the app developer not to screw it up. If they set the foreground colour but not the background, or vice versa, they risk getting both so close to each other that the lack of contrast makes text illegible. This is so obvious that on such systems, the fault is totally with any app developer that does this.
A custom config can be made for each program to addresses all idiosyncrasies and that could be shipped with the distro as "dark mode" without any code change.