If that was the case why on earth would anybody buy one at launch, pay a price premium and have no 1st party games to play?
I may not buy Nintendo consoles for 3rd party games since most multi platform games are better on the PC, but you can't say they aren't important since Nintendo make a lot of money from licensing fees, which they won't get if 3rd party devs are abandoning the console, which currently they are.
Take Injustice for example, the PS3/360 versions have had patches for balance changes, a DLC character etc, the Wii U version hasn't even been patched, even when 3rd party games do come out they don't seem to be supported very well.
The Gamecube had far better 3rd party support and had almost all of Ninendo's 1st party games and it still sold well under what Nintendo had predicted, people seem to think Nintendo is going to release a few 1st party games and then the Wii U will sell as good as the Wii did, it won't.
Not to mention Nintendo seem to be having trouble developing games for the console in an efficient way, since Pikmin 3 which obviously started out on the Wii is still miles off, with no EU release date.