Apple's defense is that their walled garden and strict rules are what's stopping their ecosystem from becoming a cesspool of scams or fake or harmful apps. User

Apple's defense is that their walled garden and strict rules are what's stopping their ecosystem from becoming a cesspool of scams or fake or harmful apps. Users (who are not "power users") trust Apple's ecosystem. The user experience of installing from their app store and using their sign in method is so much better than the experience of installing from the web and signing in via other methods. It frustrates me that the entire industry failed to create a suitable sign-in option and Apple felt they had to step in to create something with good UX while respecting users' privacy. I'd love for the iOS ecosystem to open up more, but I also know it would be exploited easily and create an industry-wide race-to-the-bottom for UX and privacy.