DS Daily: What drives the remakes?

Yesterday, we put up the first part of a two-part series about the flurry of remakes that are headed to the DS, and today, we'd like to pose the same question to you ... or at least, part of it. What do you think is driving the remakes on the DS? Sure, remakes come to every system for a variety of reasons, but the DS seems to be home to a lot of games, and we think it's for a variety of reasons. What's your opinion? Sales? Popularity? Technology? Portability? Or something else?