[Namidairo]

The major carriers perhaps, but support among the MVNOs isn't universal. Number sharing support for smart watch usage is almost non-existent among the MVNOs in Australia.

Eg. ALDI (yes, the German supermarket chain run a MVNO in Australia), have been saying esim support in the future since 2021.

[scarface_74]

In the US, the overlap between people who would buy the latest iPhones and the people who use MVNOs I would suspect is practically non existent.

The MVNOs here mostly market older, cheaper iPhones.