Yes, accessibility is a process. Even if we attempt to provide accessible content based off of the current WCAG standards, the target will continue to move because the number of disability groups is likely to increase. Of course, that doesn't mean that we should throw our hands up.

It may speak to coordination (or lack thereof) among AGWG, browser vendors, and WhatWG.

That's one of the reasons that I think we need to seek accessibility instead of compliance, and that good faith efforts should be rewarded.

I know it's frustrating work sometimes, but I am glad there are those out there like you that are doing their best to make content more accessible.