The 3DS isn't doing great. While it's not a failure on par with the Virtual Boy, its reduced price and sorely lacking library already strikes most of us as Nintendo abandoning the system early.
A full system redesign is supposed to follow next year that will "not push 3D as hard as the current 3DS does" and will, presumably come with the extra analog stick already attached.
With no official word from Nintendo, this is pure rumor, and it could be completely off-base. But as someone who isn't much of a fan of 3D in any form anyway, I wouldn't mind a 2D 3DS on store shelves.