To be fair, the amount of people who own Wiis doesn't mean sh*t to developers in the long run for this. They care only about how many copies their game sells. If the game sells enough copies to be profitable and sells more than their last project, they're doing very well regardless of other factors.

I just though that a metroid that uses both 3d and 2d would be cool. It would be new and I would love it. YOU get the side scroller features that you get in the 2ds but then you get the first person that you get in the prime series.

Being in a "hybrid-genre" Metroid Prime has always had trouble selling at a level similar to games which are similar in quality and content but they have still been amazingly profitable games. I don't see another Metroid Prime game for several years though because I expect Retro to move onto other projects and for Nintendo to leave this series on the back-burner.

 I don't ever see another prime since 3 was the last but I see other metroid games. I think we could see another 3d metroid in 3 or 4 years. 

None ,the guys of retro are taking a break from the metroid franchises but Im sure there will be another metroid the ds and probably a wii ware game.

I wouldn't be surprised to hear of a MP Trilogy being released with updated Wii controls....

Of course I would prefer an expansive 2d game ala Super Metroid but in a larger world.