Comment by mrweasel
In general I'm not convinced that these "no Javacript" frameworks will last, and to some extend you going to have to re-learn a lot. That's not to say that the idea isn't interesting.
While I have no idea how this would work, I think it would be more useful to have tools like this as a sort of template language for something like Django or Flask. So you get the mature frameworks on the backend and something like Rio to generate the backend, within the context of Django/Flask/Bottle/whatever.
Some modern web applications do need VueJS, React, something like that. CRUD apps mostly don't, but we are way past CRUD apps for a lot of thing. You can maybe get away with calling Asana and Jira CRUD apps, but you can't do Figma with just Django.
Agreed. There are legitimate cases for using SPAs, but often CRUD will suffice.