> It's not that it's public. It's that it's in use.
And an API that isn't public can have its use restricted to a controlled set of environments and places, which inherently makes it easier to update.
> Apple can continue to update it's API's and devices at any rate it pleases. If the 3rd party devices don't updates fast enough to follow, well that's their problem.
Until the EU decides that a public API that changes without warning and "arbitrarily" to suit Apple's needs is also anti-competitive. An argument that would easily be made the first time Apple shipped an update to the API that broke a bunch of third party devices even while their own devices continued to work fine because they received an update at the same time, or even early in preparation.
Again, my argument is not that it is impossible to make a public API or to transition that API. My argument is that a public API by its very nature often implies a slower pace of change. Even in your examples, SSL and TLS upgrades often happen over many years, with deprecated older versions being supported along side the current version for a while.
In fact, TLS is a great example of this, where TLS 1.1 had fixed the vulnerabilities that made the BEAST attacks possible, and yet in 2011, when BEAST was discovered, it was still a problem because in 5 years, TLS1.1 still hadn't had a lot of adoption. Or consider that TLS 1.3 has been out since 2018, and yet I can still connect to this very site using TLS 1.1 with weak encryption keys. In fact, if I change firefox to require TLS 1.3, I can't even connect to this site. Or consider further that initial TLS 1.3 rollout was hampered by middle layers that had implemented the spec badly (https://blog.cloudflare.com/why-tls-1-3-isnt-in-browsers-yet...).
Again these are not insurmountable problems, but they are problems inherent with a public API or protocol that multiple vendors are implementing, and problems that Apple either does not have to deal with, or deals with on a much smaller scale with their private internal APIs and therefore can move faster when iterating on those APIs.