I can hear it now:
"We're not being anti-competitive. Our users, and US courts are demanding we lock down our users' privacy. We have no choice but to comply. Maybe Google and Facebook can work out some other way to make money?"
"Oh, yeah, I guess you're right? They are pretty big competitors. Pity that. Oh well, what's to be done? We're all obligated to operate within the confines of the current legal environment after all.'
[0] https://www.counterpointresearch.com/global-handset-market-o...
But, Apple lock-in, and other self-serving restrictions, may be the reason we don’t hear about many potential products that never make it. Anti-competitiveness protects margins in the long term by avoiding pesky upstarts and challengers that might change the playing field.
(Not critiquing any privacy issue with this comment. Just competitive issues from Apples view, and the view of all the non-Apples, in the abstract and the real.)
This is where its dominance may require antitrust action at some level. Or Apple is unlikely to appreciate restricting itself equally to others.