Choosing, for example, whether to use a div with a click handler, or a proper button, is a decision you need to make regardless of whether or not you're using a framework.
So it seems incorrect to say that you lost accessibility in this case due to the framework. You lost accessibility due to developers who didn't understand the web platform well enough to design proper accessible controls. If they hadn't used a framework, they'd probably still not have made the site accessible.
And i actually think that it is _better_ for a developer not to have to do their own accessibility controls, but delegate this problem to the component framework. They have to know about the problem, but not have to spend cognitive budget thinking about it while they compose their UI from framework components - this should _automatically_ be taken care of by the design of the framework.
> entirely on you
of course - choosing a framework or hand rolling one makes no difference. It's still not production ready, if it doesn't have accessibility built in.