less javascript + less dynamically loaded/changed content is the solution to web accessibility
Source: I used a frontend developer working on a big bank frontend. The existing UI stack was horrendous and deadlines and bank politics wouldn’t allow you to refactor anything. Just build shit on top and hope that Jenga tower of a web application doesn’t fall apart halfway there.
I believe the most important point here is the internal business politics that allows such an approach in development. Once I was curious and tried to find out how private banks' front ends look, and I was surprised to learn that they used minimal frameworks (sometimes none) and obviously zero external resources.
One thing is clear: if the business structure allows 10MB for a login page, this is not only about the front-end, this could be about all services and could spread much wider.
BTW, the bank that we use (with the 10MB login page) totally sucks in every aspect of business relations as well.