A good UI library should definitely be accessible once it's in a mature release, but that's a fair bit of extra work to do up front when things are likely still in a state of flux; and since there's no guarantee there's even sufficient interest in Yet Another UI Library to get an upswing in usage, it's very possible no blind user will ever be exposed to a site powered by this in production at all, ever.
I'm not trying to say we should ignore blind people overall, but this comment is always in the top spot on every single new UI library and it's rather tiresome. How about some actually constructive criticism on the structure of how this library actually works?