What you are not realizing is that the purpose of thunderbolt is not data transfer or even video (in fact Thunderbolt only carries DisplayPort and doesn't actually implement it's own video standard). For most people USB 2.0 transfer speeds are fine and nothing more is needed. Transfer is usually constrained more by the slow flash memory speed and not the protocol. USB 3 and Thunderbolt however are not meant to do the same thing, even if sometimes they are marketed as such. Thunderbolt is made to be an expansion, not accessory, interface designed around PCI express. It's purpose is to enable, hardware devices like high end graphic cards, raid devices etc. to be connected to a machine seamlessly. The idea is so that you could have a relatively low powered laptop, take it on the go, but be able to dock it or just connect it to very powerful hardware when you have a need to. Or you could do a hardware upgrade without having to open a computer up, which could also enable machines to be made smaller (Plus, lets face it most people find opening their computer up to be "scary"). Thunderbolt could also be used to connect a computer to a very fast mesh computer processing network enabling one to tap into huge amounts of power. Thunderbolt devices require more processing power and chips on the device end compared to USB as all devices are PCI-E devices. This makes it faster as processing is offloaded from the computers processor (unlike USB) and instead the devices are smarter. This means thunderbolt devices cost more, but at the same time have much more capability. USB really is a fancy version of a serial port and even with USB 3 isn't really meant to add hardware to the computer apart from modems and some storage. The one Sony thunderbolt docking laptop was a good example of thunderbolts power with a high power external thunderbolt graphics/bluray dock. While USB 3 for the most part just make things faster, thunderbolt could revolutionize computing as its basically PCI-E external. For the average consumer USB 3 is pointless as they don't feel USB 2 is slow so why would they pay more for 3? Professionals will never embrace USB 3 either as it doesn't provide half the expansion/bandwidth of thunderbolt.
While I would agree that this dock is obscenely overpriced for what it is, this is not the full extent of what thunderbolt is capable of. In the docks defense though the dock does have to have its own Network, Sata and USB controllers/chip-sets which do add up. If they could get the price down to $200 it could be a winner, though I doubt that will happen until more thunderbolt laptops are out in the while.
