You still need hardware significantly more complex than would be otherwise needed for a device for which USB 2.0 speeds were already much more than required.
I don’t really understand how USB stuff works (what is the difference between a hub, interface, and controller?) but from what I’ve seen I think a hub supporting 20gbps would probably be in the 5-15$ range and probably not larger than a few centimeters
If you have multiple ports driven off the same internal hub, they will share bandwidth.
You still need hardware significantly more complex than would be otherwise needed for a device for which USB 2.0 speeds were already much more than required.
I don’t really understand how USB stuff works (what is the difference between a hub, interface, and controller?) but from what I’ve seen I think a hub supporting 20gbps would probably be in the 5-15$ range and probably not larger than a few centimeters