Apple's competitors are capable of competing with them, so long as Apple doesn't preference itself unfairly
[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.