I think the iPad pro etc lives in a different category. They're all high end devices that are bought by people who either like tech, or use it for work. People who want the latest everything, and are happy to change things like cables to make it happen.

The iPhone at this point is just a phone. I suspect most people own them because their good tools for everyday life. Based on an observation of my parents, their friends, and parents of my partner, I would say that most of them don't give a rat-arse about the port on the bottom. They just want the phone to work with the cables they already have. For many of these people an iPhone and iPad Air will be the only computers they own.

I appreciate that my point is a little undermined by the new iPad Air, but I suspect that iPhone will go to wireless only charging, something the iPad can't do, and Apple don't want to go through two transitions in less than 5 years.

USB-C to USB-A dongles were and are cheap, and USB-C/TB on MacBooks enabled one-cable docking solutions for the first time on the MBP platform so people actually welcomed that.

>They didn't see this as a problem when they introduced lightning

Apple now ship more lightning cable in a single year than all the 30 Pin exist in the ecosystem combined. The scale is just different.

And this is not a problem for MacBooks and iPads. Nobody docks them in a cradle or to a car phone stand.