Don’t get me wrong, I would love to be able to use ipc-2581. But what’s critical for KiCad users is the manufacturer support. I don’t see much of it amongst the potential manufacturers. With “potential” I mean those used by the large part of KiCad user base - hobbyists and small companies - which means cheap. We choose the manufacturer by price, speed, quality etc., not by file formats. Everyone accepts gerbers anyways. Ipc-2581 would be plus, not a requirement.
Even then ipc-2581 would be beneficial because the customer could get rid of the problematic multiple-files-multiple-formats-check-everything-twice-make-mistakes-communicate-with-manufacturer cycle. I would love to see it supported. But as the things are right now, even if KiCad would support it, I couldn’t use it.
Pretty much everyone you find if you try to find a cheap(ish) manufacturer. Can you point even one exception? For example from the list in https://pcbshopper.com/ ? I haven’t gone through them but I have visited several manufacturers’ websites and don’t remember seeing ipc-2581 mentioned.