Apple recently started the switch to USB-C, so I don't understand this comment. All of my Apple devices charge with USB-C now
The notion that the EU forced Apple's hand with the iPhones a year after that (and not that Apple continued a transition that was already in progress) is some people's favorite conspiracy theory.
I suspect the iPhone was last because it is the most popular device. They don’t want to do anything risky, and it would be good if people already had a bunch of USB-C around the house before the iPhone switch to make it less impactful. People were very upset when Apple moved away from the 30-pin connector, because all their accessories became obsolete overnight. They promised Lighting was designed to last for the next decade, which is about how long it lasted.