Does the distinction actually matter though? By constraining what developers can provide, you're automatically constraining what users can use, so I don't see how it makes a difference.
It's silly to cast the mobile browser wars in abstract terms, as if JoesOwnWebBrowser is going to be a thing tomorrow. It's Google and Apple, full stop. Google is leveraging their titanic web properties and mobile ecosystem control to push Chrome. Apple is using their control over the iOS ecosystem to retain Safari. The choice is whether the mobile web has two relevant players, or one.
That's an important distinction. Apple's monopolistic practices prevent better software from succeeding on phones, and I'm disappointed that Apple's anti competitive behavior is excused.
Note: UC Browser is a huge privacy threat and please ask friends and family to uninstall it. But the point still stands.
And here's a real world example: even if v8 was a better runtime for React Native it still wouldn't be allowed into iOS.
I think so, yeah. Or at least, the idea that the rendering engine is all that matters for a browser is not something I’d just accept without explanation.