By the time iphone7 is released, every other major phone will have already adopted USB type c. Maybe people will be happier that they can borrow a friend's android's cable since it is usable. USB type c ports will be absolutely everywhere soon anyway.
I don't think Apple is afraid of pissing people off. E.g., they made the macbook air have just one port usb type c port... (I must say I rather like that they are willing to do this, these are the decisions that really establish usb type c port! I just wish they'll do it with iphone7 too)
Heck, I stayed in a hotel once that had a speaker/alarm gadget with an iPod dock connector in every single room. All obsolete now. Would they do it again so few years later?
Android users might be happy to have Apple switching to USB-C, but the majority of Apple's customers wouldn't be.
As to 'used on more than one brand's devices' - what benefit do you think his provides?
It made sense to move to USB-C on the MacBook where it replaces every other connector and makes their product more aesthetically attractive and thin.
On the phone they already have a thinner connector with a much thinner plug. It also allows them to have a high-markup proprietary adapter market.