They are not rare, and they are not collectible -- this is a misconception.
The challenge with these games is that they just came out within the past 2 months. Second, unlike the orig GBA versions, these support DS multi, as well as just having a DS label which speaks to parents and impusle buyers. Also, they are distributed wholesale style, so the distribution of these games to retail is different than what most people are used to. Being distributed thru the wholesale channels means that they don't end up in Gamestops, and parents who use Gamestop as a baby-sitter while they shop elsewhere can't find these games there, so they are pushing up the auction values.
I would not invest too much money in these, as they will be back out soon, given how lucrative these licenses are for the publishers.
It is a misconception that these are Atari licenses. They may have been at one time, but that is no longer the case. Apparently I don't know what I am talking about -- just call me a DS Noob.