USB C would be as if we could already plug arbitrary lamps into arbitrary sockets, but then someone decided the same socket that powers lamps should also be able to refuel a car and now you have to plug and pray with five different cables before your lamp will work. Also if you use the wrong one it will spray gas all over your lamp and catch fire.
Spraying gas and catching fire is precisely what it won't do. The spec is conservative about capabilities; assuming devices aren't out-and-out lying about physical capacity (which is out-of-spec), it's designed to err on the side of safe conservatism.
If you plug the lamp into the gas hose plug, it just won't turn on.
Yes, because people worked on implementing a standard, and we are all better for it.