I think you misunderstand the meaning of "developer device". This time it doesn't mean "random device that is of little use to the mass market but some developers may enjoy toying with" but "early device for developers to create applications for a new OS before it gets released to the mass market". Even after the decision to go with WP7 for the mass market, the concept is still the same. These are exciting times, and many things will become much clearer soon.