I have to admit with shame I know sparingly little about the accessibility when building web apps, but with Wasp we think it could be a really valuable feature to offer - guaranteed best accessibility practices - it should be integral part of Wasp.
Why doesn't screen reader detect it -> because URL does not change? What if SPA updates URL via history API, does that help? off-screen ARIA region sounds like something we could generate with Wasp automatically.
Once we reach some level of stability, we plan to put more effort into accessibility -> if you wish, write a comment on our GH issue and we will be happy to include you in the effort when we work on it, help from somebody experienced with accessibility would be great.