Some argue the elimination of the ADB and other ports with the iMac helped popularise USB.
http://en.wikipedia.org/wiki/USB#Connectors_types
ubiquitous, indeed.
Though, I vaguely recall reading that some future iteration of USB is going to go that way, it'll be nice to get that finally.
I think the opposite. More than once I've heard people asking me for a charger or phone cable. When those people happen to be not with Apple devices everything works just fine (microUSB, you know). When they happen to be with Apple devices they can't use them and need to look further.
They do care, since in such scenarios it's clear for them that Apple cripples usability of their devices for no reason by preventing basic ports interoperability. I often point it out for them in a sense "so stop using Apple". They say "yeah, I know it's stupid, but what can you do".
With iPhone marketshare still above 40% in the US (and holding steady), I think it just depends on which phone-demographic bubble you're in.
Outside of the US, I'm sure things are quite different. Aren't iPhones in the EU required to come with a MicroUSB adapter now, though?
Not sure whether EU dictates such thing as common ports, but I wouldn't be surprised if they do.
Heck, some of Apple's "proprietary connectors" even become the standard, such as Mini DisplayPort.