[cesarb]

> There is no such thing as a USB-C hub. The protocol doesn't support it.

Did you read the protocol specification? (It's freely available, with no paywall or even login wall.) The protocol does support a USB-C hub. Actually protocols, since there are three separate protocols involved, each on its own set of wires: USB 2.0, USB 3.x, and USB-PD. Each of them has its own support for USB hubs. The hub support for USB 2.0 and USB 3.x is the same as in the older USB hubs with the USB-A and USB-B plugs and sockets; only USB-PD is new (and has long chapters on how power delivery works through hubs in several different scenarios).

The only gotcha is that Thunderbolt 3 does not support a USB 3.x hub (but this is fixed by its successor USB4); this is worked around by including a full PCIe USB 3.x host on the Thunderbolt 3 device, since Thunderbolt 3 can pass through PCIe and Displayport at the same time (USB4 adds USB 3.x to the passthrough).