What apps are being made elsewhere that aren't being made for iOS? And how successful/popular are they? Saying there are plenty, without evidence, is a counterf

What apps are being made elsewhere that aren't being made for iOS? And how successful/popular are they? Saying there are plenty, without evidence, is a counterfactual that can't be proven. There may be some apps that aren't made on the margins, but on the whole the rules make the App Store a better experience, and it's their prerogative to choose that over the marginal app.