I'd argue Google doesn't owe you "discoverability". You're absolutely free to sell your app to users with no involvement from Google. If you want Google to help you advertise and distribute your app then I see nothing wrong with them imposing some conditions on that.
This is unlike how Apple does things where they literally block your app from running on your customer's devices unless you get Apple's approval (and pay them), and there's no option whatsoever to cut them out of that process.
Some of us Android devs would argue that literally blocking an app from running is little different than building an ecosystem designed to minimize non-Google Play methods of distribution.
