USB has 4 pins and Lightning has 17, that ought to tell you something.
This article explains pretty well why USB won't work for the iPhone/iPad etc..
http://www.cultofmac.com/178093/the-future-of-apples-dock-connector-feature/
Apple will never adopt Micro-USB, not out of spite or trying to "control" everything. It just plain can't handle all of the devices/accessories it needs to communicate with or control.
That article explains nothing except the fact that 30 pin connector has Firewire's 8 pins, 3 pins for video out. At least on their shortened list. Move that to Micro USB, and it actually makes sense. But again, I think it's more of a greed and control issue, than technical.