Apple was already well under way on their USB-C transition. They literally shipped the first all-USB-C laptop in 2015. Not the first Apple laptop. The first laptop full stop. The iPad Pro switched to USB-C from Lightning in 2018. Every year since, fewer and fewer devices released with Lightning and more and more with USB-C.

If you need more evidence, literally just consider that Apple never bothered to invest further in Lightning. There were no further speed bumps. No updates in the USB protocol version supported. Even charging, USB-A to Lightning has been capped at a pitiful 12W. Does this seem like the behavior of a company that wants to stay on Lightning?

The iPhone would undoubtably have been USB-C in a generation or two even without the EU’s involvement.