I'm thinking Nintendo might offer a later 3DS model without the 3D.

[Untamoi]

Well, if they do that, they couldn't use name 3DS for that device anymore. Just like you said, it is in the name, so they will never do handheld with name 3DS without 3D. Sure, perhaps they could use name 2DS or something like that. But I don't think there will ever be 3DS model without 3D.