For 90% of the market though, that adds a $200 cancellation fee to buying a device which requires a contract (or forces them to delay their purchase for months). So that $299 Dell Streak actually costs me $499 (because I have to get out of my current contract), and I won't be able to get it at $299 until like next June or something, by which point the market may (will) look different.

Phones and non-phone personal electronics are different market niches, because they attract different clienteles. Maybe in a decade when unlimited data is like $10/device that'll change, but for the foreseeable future, most non-upper-class people aren't going to have more than one phone contract per person.