Well I mean, the WiiU arrived only one year before the PS4 and X1. It seems to me they just wanted to be first out of the gate with their 8th gen console. With that in mind, I don't think it was ended too early at all. The WiiU failed for a number of reasons, but the Wii being ended when it did was not one of them.
As Curl-6 pointed out however, they did slack on the software front in the end of its life. I will agree to that.