It isn't even that hard, like I've been able to update the parts of MUI and reactstrap that my applications use even to calculate coordinates for portalized flyovers correctly. I could send but I just don't want to do the 5x work to do all the other components I don't use and then face the politics of a community that probably doesn't care if disabled people can use their products or even if they can check the boxes and pass WCAG. <dialog> is easy to use with HTMX and just a touch awkward with React because React insists on being level-triggered in edge-triggered situations but once you have it coded up <DialogsThatReallyWork/> just work.
But then again it boggles my mind that you can pass WCAG with those "is this a motorcycle?" things or that stupid anime girl you see on Linux pages or a GDPR popup and you can. People will say "what if you have to support WCAG and GDPR?" and I say "sometimes you have to make a choice", I mean a11y work is damned if you damned and damned if you don't, just damned all the time and personally the EU screws up my life a lot more than Iran ever did.
It is a problem that the experiences of disabled people are erased by the current regime, I haven't once seen an organization actually ask a disabled person if they can use the site or how it can be better.
Also I think accessibility tools are trash. If I start NVDA on my dev machine I have to power cycle it to get control back. Microsoft Narrator sorta works but the more you use landmarks and other aria-markup the more it starts blurting out things like "LANDMARK NAVIGATION LANDMARK!" in the middle of reading something even thought Siteimprove thinks it is all peachy. Is it a fail? Or did the tool fail? My tester or myself can look at an application as a sighted user and test it in Firefox/Chrome/Safari and say "it works" but it is not clear at all what the "definition is done" for testing with screen readers.
I hear JAWS is better than the others but it costs about as much as a car. In the meantime though I know when we don't use <dialog> we fail and I've seen a lot of third party modals that don't use <dialog> that all fail.