The JSON Schema spec was abandoned by its original authors, and was picked up by a series of other people with varying levels of standards experience (myself included).

Personally, I had some promising support from my then-employer (including an IETF connection), but then it kind of petered out, and I was buried under other stuff and had to pass it on. The team who picked it up since them seem pretty on-the-ball as far as I can see, so I would still recommend it as a useful project to contribute to.

It is supported by some tools - last I heard, Visual Studio could use JSON Schema for autocomplete and validation, as well as a couple of databases. I used to get a few million NPM downloads a month on my validator, so someone's clearly using it.