Well if apple invented it i guess it will be as useless as the Firewire and Thunderbolt ports are nowadays, it will have a short term, expensive set of peripherals, and then fail.
seems when apple picks a "proprietary" port, its basically a nail in the coffin for that tech
Lets just hope that because its USB, and an open standard, that we see this adopted across the board, including apple dropping the lightning cable for the iPhone 6s and next gen iPads, i would love a world where ONE cable does everything from charging my phone/laptop/tablet to hooking up my glasses free 3D ultra 8k monitor to my Nvidia Titan black platinum ghost death ray power sucker 2000 edition in a couple of years.
Non of these are proprietary and Apple is the 4th company selling USB C products on the Market.
As for the one cable to rule them all, it's not going to happen as that cable in Thunderbolt. Unfortunately thunderbolt is expensive and not what 99% of the consumers want, because of this we will have to standards side by side. Thunderbolt will continue and be for the enthusiast, prosumer, and professional market.
My biggest question is what will Apple do with this fragmentation. Will they make a 5K thunderbolt display which will not be compatible with the MB or will they just make a lower end USB C display. I have a feeling Apple will offer a USB C display and let the professionals buy third party 5K plus displays.