Literally Nintendo handhelds only survive because of the INCREDIBLY SUCCESSFUL life support provided by their flagship brands.
In order of importance to Nintendo
>Mario
>Zelda (Even if Pokemon sells a fuckton more as a franchise)
>Pokemon
>Smash Bros. (we have yet to see how it will fare on a handheld)
>Donkey Kong
>Fire Emblem
If you put these (exempting Mario, Zelda, and DK, which started on consoles anyway) on consoles (hell, or even non-Nintendo PRODUCTS in general), you will KILL EVERY FUTURE NINTENDO HANDHELD. That is, unless Nintendo actually decides to make some new, good franchises that can keep the 3DS and its successors profitable.
Notwithstanding, I'd like to see Nintendo venture into making forays with these franchises on consoles and maybe even competitor consoles. A barrier already fell when Kojima Jewed Nintendo to let Solid Snake into Smash Bros. Brawl. (and letting SEGA's Sonic in too) Who knows what could happen in the future?
