Who is using mobile without JS? They are going to have many problems beyond collapses... Likewise, crawlers these days generally run with JS enabled in a browser/VM because so much breaks completely if JS is disabled. This is not a real problem, sorry, NoScript fans.

(Anyway, if you are using CSS + the relevant semantic HTML elements, it can be more accessible, not less, because you are expressing priority and emphasis, so they can skip over collapsed stuff. Although I have my doubts whether screenreaders etc make any good use of it, given that they apparently still do not do basic things like stripping soft hyphens.)