Seems like this is a feature you could demand if you were a big enough client of their enterprise products. Better yet, get a critical mass of big clients together and push for it. You could probably do this by showing up at a product-specific conference and networking with the other devs who care enough about the tool to show up.

Also, if this is a genuinely useful thing to have, you could probably monetize it directly. Decouple the schema repository from your primary application and sell access to well-validated, performant client libraries for popular SaaS APIs.