We actually have had literate programming for a while, it just doesn’t look exactly how it was envisioned: Nowadays, it’s common for many libraries to have extensive documentation, including documentation, hyperlinks and testable examples directly inline in the form of comments. There’s usually a well defined convention for these comments to be converted into HTML and some of them link directly back to the relevant source code.
This isn’t to say they’re exactly what is meant by literate programming, but I gotta say we’re pretty damn close. Probably not much more than a pull request away for your preferred languages’ blessed documentation generator in fact.
(The two examples I’m using to draw my conclusions are Rust and Go).