That works great if you're starting from scratch, but not so much if you're on a brownfield project. The way the generators are written, even generating a new endpoint can't be done after code has been written because it generates a whole file with route stubs.
Agreed, but if you’re asking for a solution that will generate a spec from your code, the more proven path is to generate code from a spec. Gives you more and costs less.
In my opinion the problem is that there’s some APIs that are impossible to represent with OpenAPI — that’s the real challenge they should be solving with this version, not reducing spec line count.