You can’t choose what happens is the default on an iPhone. If I want to use Gmail to open mailto links I cannot. If I want to use chrome to open web links by default, I cannot.
On Android you can pick whatever apps you want as the default.
I might have misunderstood what theBobBob meant with "default apps" completely, but that was not how I understood it at all. As far as I understand, he talks about disallowing apps on the App Store, so this would be a completely different point (to which I agree, setting a different browser would be nice).
They don’t allow apps that have similar functionality as well. On my phone, but when AirPods came out they pulled an app that helped you find your AirPods from the store because they included their own version of the same tool in an update