I get that, but given that some countries have insanely restrictive
Wi-Fi data caps (I heard 200GB, which I would probably blow through in a week or less), I don't see the problem. Even if updates-over-4G are disabled by default, power users should be able to turn it on. My grandma has 70GB for 15€ a month; she only makes FaceTime calls, so uses on average 4GB of data a month. I'd love to use SharePlay to share her screen, and teach her how to use her phone, but that won't be possible, because she can't install the update; it'll have to wait until the next time I travel to see her.
I hear that Android lets you enable updates-over-4G, but allows carriers to block the feature. That's detestable! Surely, if I pay for data, I should be able to use it for anything (legal) I deem important? I don't like corporations making those decisions for me.