One factor in 3.1 support is that it came out more-or-less concurrently with JSON Schema draft 2020-12, and depends on it. 2020-12 support has recently become more common across more languages, and we're seeing 3.1 work pick up the pace a bit.

But (from years of experience working on these standards), there is _always_ a lag in adoption. You can't just sit and wait until everyone "catches up" because that won't really shorten the lag to the next major version (OAS 3.1, despite the numbering, had significant enough changes to lag like a major version).

So while I'd agree that it's slower than if there were a clear and well-funded owner of things (which is closer to the situation with AsyncAPI), it's not _unusually_ slow as these things go.