Make hardware that is close in performance & features to the competition.
Developers will port to a minor console if it's almost no extra work or compromise. GC was like that. Porting from PS2/Xbox to GC was easy. I did it for some games at the time.
Since Wii & Wii U Nintendo's systems are almost a generation apart from Sony & MS, and devs don't like that. It's not only about effort & cost, but also about developers being sick of developing on that older technology for diminishing return.
If Wii U was selling well they would make an effort even if they don't like it, but since Wii U sold like crap it made the choice very easy for developers to not bother.








