I like the idea! Let's start with v1.0, and then just let our PR team decide on the next versions
Nah, we cant go with 1.0. Bad for adoption. Since we can push 10Gbps easily, and maybe up to 40Gbps if we try hard, lets call the first version usb "ultraspeed" and let the marketing guys work with that!
How many parallel differential pairs can you have before it's no longer serial? Hah.
You can have arbitrarily many, so long as the serial lanes are independent of each other. PCIe can have lots, for example. Because they are independent, they won't suffer from clockskew problems that made parallel signaling impractical at high speeds and it's often not required to connect all of the wires (e.g. an x16 card hanging out of an x8 or smaller slot) .
That's just kicking the can down the road to even less efficient software that must now manage synchronizing all the lanes.