I also work in education and agree. I have also had direct calls with the Feds who enforce accessibility, and their stance is evolving. The future trend is not going to be just "can it be used?", but "is the experience as smooth as it is for fully abled users?"

As an example, if you make mouse-based users do something in 2 clicks, but keyboard-based users tab through 100 elements to do the same thing, that is going to be flagged as not accessible even if it does pass WCAG validators.

As far as startup MVPs go, I agree completely that it isn't required on day one, but the design should take it into consideration to be ready for the future.