They do not "under-spec" their phones. They spec them to exactly what they need. Over-speccing a phone is useless and a waste of battery life. Remember: YAGNI.
YAGNI is bullshit for infrastructure (including platforms). In fact, the opposite is true - the more you give, the more interesting uses follow. Every extra sensor, every screen resolution increase could be dismissed on the basis of YAGNI. Hell, that 64K quote comes to mind.
Also, battery life and Apple phones - that's rich too, given that Apple was found to make iPhones reduce their computing power over time to preserve battery life, instead of educating their customers that batteries are not magic pixie dust, and they degrade over time.
Bwahaa, is this not the same Apple we're talking about? The one that eliminates headphone jacks and Flash and usb ports and cd drives and anything else people hold dear all in the name of YAGNI?
If they could eliminate even less, I'm sure they would. The fact is, we need exactly what we have now, nothing more and nothing less.
I never said I agree with what Apple does. In fact, I strongly disapprove of the decision to drop the headphone jack from new iPhones, and it further alienates me from their platform.
With that mindset, I demand Apple make an iPhone with a serial port and a built-in fax machine given how often I need a serial port and the ability to fax a piece of paper.
I find myself morally outraged that they did not consider my very common use case when building their smartphone.
Not sure about the iPhone, but on Android phones you should be able to do both of those with appropriate USB-to-$whatever connector and an app. And this is possible precisely because people didn't go all YAGNI about a proper micro USB port and ability of apps to use it.