Earlier quoted context omitted.
The ironic part of this is that if Apple allowed alternative browser engines, I guarantee you it is only a matter of time before you see Electron apps bringing their own browser engines with them to iOS. And not long after before Hacker News is screaming and moaning about it (like they do for Electron on desktop) and begging for Apple to stop it.
HN already screams and moans about mobile apps built with PhoneGap/Cordova/Capacitor/Ionic ect. for not being "native" at the same time as promoting PWAs and complaining that apple doesn't support them, ignoring that PhoneGap, Cordova and especially Capacitor give you that functionality (mostly). I think that says more about HN than Apple...
I'll admit, though, I'm in the "I really want native Mac apps" minority :)