I like ConTeXt (still do, I liked its approach when I first encountered it). But the project is more the ongoing private tinkering of a small in-crowd (that communicates with some followers).
ConTeXt is managed a bit like a small group of researchers sharing a couple of complex and undocumented models/programs and tinkering with them as they go along. It’s an activity without formal design, but with a lot of trial-and-error/testing.
Given that status (and the fact that it has had that status for over a decennium), I don’t expect it to ever become a serious product that is (semi-)professionally managed. I prefer content over management every day, but something like this needs some minimal management. That requires both time (=money) and capabilities. Besides, the tinkering researchers may not be inclined to do that, they want to tinker.