I do use ChatGPT to research things, but I don't usually see that as accessibility solution. I completely agree that screen readers and browsers would benefit from AI, as they already are; Chrome and Edge can generate missing image descriptions. AI can certainly enhance accessibility, but it can't replace the existing technology that already works quite well a lot of the time.
The other positive about AI for accessibility is that the frontier models have a good understanding of what works. Instead of learning all the guidelines, you can just ask an agent to review the page for accessibility and fix any problems.
I realise I am only looking at it from a screen reader point of view, and yes, we are quite a small minority. But good universal design helps everyone, whether they just need to zoom the page for comfort without it breaking, their eyes are not that of a young person, they have dexterity issues using a mouse, and many more. Accessibility in general isn't serving a tiny minority,. I imagine most of us will come to appreciate it in some way.