I think if you adjusted his statement to be - not use apple’s “everything” software ecosystem - it would be possible.

Core device apis yes, everything else, maybe not?

I think we could roll our own UI - I think we can roll our own payment systems - I think we could roll our own media display.

For the primary iOS app I work on I need vulkan, gps, touches camera, sound, and phone rotation. (And standard os services)

I don’t need anything else.