Your average and generic UE game does not make Nintendo hardware jump off the shelves like it does for sony and microsoft. And Nintendo knows that.
They would rather develop their own engines and tools and 3rd party exclusives using such tech and building 3rd party collaborations like monster hunter, fire emblem x something and W101.
An optimized, specifically tailored in house engine is better, more practical business wise and cheaper than whatever epic could do on that regard porting UE4.
Its not in the pipeline for NIntendo and they don't give a damn about it. Thats why your iPhone 3G has UE3 support but 3DS does not. Its not because of hardware limitations.







