I mean they could. But it would only solve one side. I dont think the original drafters envision using usb as a charging platform but a data transfer between thousands of different devices and host devices. I dont think they intended for most portable devices to have one side basically permanently fixed.
For exampe for each mini and micro type B connected theres a mini and micro type A connector. But ive never seen one in the wild, but its suggestion the intention for the usb drafters.
not really, in 2007, USB wasn’t even the main way to charge phones. most manufactures were using their proprietary connectors. I recall Nokia was using their barrel plug well until they sold to MS.