USB-C isn't some new fancy connector technology that will fully mature in 2020, it's just USB3 + power + pass-through for a bunch of other connectors.

It's not a new connector, it's a connector transformer rather. Only that doesn't actually work in practice, you can't connect four HDMI<->USB-C adapter to the four USB-C ports of the MBP and expect them all to work. Similarly, I can't imagine you can connect four power supplies simultaneously and have it charge through all of them. Add a bunch of other similar non-obvious restrictions.