"And iOS 16 is about to debut so I think the iOS 13 argument gets weaker and weaker. And each version of SwiftUI brings more native components into the fold."

And therein lies the rub. Each new version brings more components into the fold... which now means that your minimum version is now 14. Or 15. Or 16.

14 is the minimum viable version, imho, due to state object. And if you want to do something simple like control focus and tab between fields you need 15.

Or if you want better control over navigation and you don't want to build your own custom navigation view stack using UIKit then you need 16.

Apple screwed up SwiftUI by not allowing an app to link with a specific SDK that's backwards compatible with earlier versions of iOS.