The pricing also doesn't make sense to me, but it may to some. I know some people, especially professionals who buy machines as part of their work expense, would willingly walk into an Apple store and buy a MacBook at its retail price. In that regard, this Ubuntu XPS 13 is not that out of line. However, in the Windows world, you'd have to be stupid to buy any computer at MSRP. In fact, it's pretty much not possible due to all the discounts thrown on. I've seen these XPS 13 Ultrabooks go down to $799 on the street, and that's with a nice Windows 8 license thrown in (and installed and configured nicely; you may not think this, but configuring up a clean Windows install onto a laptop can be easily as much of a pain as configuring a Linux install). You might not need Windows, but why not take it as a bonus even if you immediately throw Ubuntu onto the next partition? This option also means you're using the latest Ubuntu build instead of Dell's own channel based on LTS (could be a pro or con, but you could also opt for LTS yourself as well).
Canonical has the image that Dell uses for the XPS on this page: http://hwe.ubuntu.com/uds-q/dellxps/
All that said, however, I understand and applaud the idea of making a complete hardware/software package as seamless as a MacBook. I don't doubt this would make for a great option for consumers who want a smooth experience with Linux.