It's expensive, based on the price of that item above (assume they aren't just trying to gouge people, this is Belkin after all). It only goes up to 1080P. I don't know if this is technology/bandwidth limitation, or one of target market.
Note that the transmitter is the big part. Where are you going to fit that in a laptop? What kind of drain on the battery will that be? And if you're going to plug it into a base unit for power and access to a transmitter, why not just use a traditional docking
station at that point?
Some counter thoughts:
If a cell phone can transmit to cell tower why can't a laptop reach a transciever 30 feet away power efficiently.
Everything is cost prohibitive for the first couple generations.
Its a bigger software issue than hardware issue. I am sure today through blue tooth or wireless we can send the signals. Making it so the whole experience is seemless to the user and just works takes a while. (Remember plug and pray back in 95/98 days?)
One of the keys software scenarios is making sure all USB devices connected to the monitor talk through this technology too. (an example of where the current technology is lacking.)
This of course is coming looking at some of the Surface demo. I just don't think they have been thinking of it in the general use case. (with existing displays)
I think this is more important than the multi touch technology to get right.
Docking stations are proprietary. New laptop new docking station unless you somehow luck out. I am talking about a standard like USB that everyone uses and is supported by Windows as a feature like Plug and play was. Think about the media center extensibility
here. You TV could be aware of the laptop and vice versia and you could say hey look at this guys type UX.