$500 Tent Fly

Am I missing something here? This tent: http://www.rei.com/product/798882

costs $500 and has no floor and, as far as I can tell, no tent inside. Doesn't that make it a very expensive sil-nylon fly or, perhaps, tarp?

4 season tents are frequently expensive. That will withstand wind and snow better than a simple tarp.

The fly, pole and pegs make up more than two thirds of the tent cost.
The inner , what you guys call "the tent" is the cheap part.
For example : Akto inner $115, full tent $420
Franco