Curiously, third party games have been doing very very well on the 3DS... Monster Hunter, Yokai Watch, Dragon Quest, Resident Evil, Lego games, Level-5 games, Capcom games, Atlus games etc. And there was a lot of good third-party games for the Wii, notably Just Dance, Monster Hunter 3, No More Heroes, PES, Fifa, Guitar Hero etc etc etc
I don´t think that Nintendo is not "third-party friendly". After seeing so many companies showing support for the WiiU in its launch, and seeing some great games made by small developers for the WiiU, it´s clear that programming/porting games for the WiiU is not the real problem.
The problem are low sales. They don´t want to develop or port games for Nintendo´s home console because its games doesnt´sell well on it - there´s very few exceptions (Rayman Legends, Sonic All-Stars Racing, Taiko, ZombiU). They don´t consider potential sales rewarding.
In the end, it´s all about how much money they expect to get. If the expectations are very low, then better not even start work.
