Apple is very territorial about developer tools. They do allow certain businesses (like Fastlane) to operate in this space (a tacit acknowledgement that those tools provide value) yet they deny others (like Windmill) the right to operate.
This follows the typical Apple ethos of "we can do it better because we're vertically-integrated". However this only works if your product is damn-near perfect. And Apple is infamously imperfect when it comes to software/services.
On top of the competence issue, they also have no real motivation to improve tooling. They know that developers will build stuff no matter how onerous the terms, and no matter how nitpicky is their approval process.
If they re-framed their perspective, and began considering devs as "users" in their own right, then perhaps they, too, would experience the tender love + attention that Apple lavishes on its end users. But this is simply not how they view it, and there is little political will inside Eddy's org to accomplish such a shift.