Well, by "web programming" in the context of the original comment, I was talking mostly about web backends. If you mean that, then yeah, we'd develop those in one language, in fact we already do in some case (node.js et al).

But I don't qualify that as "systems programming", to quote Wikipedia:

"System programming (or systems programming) is the activity of programming system software".

and:

"System software is computer software designed to operate the computer hardware and to provide a platform for running application software".