Well I can't point to a change in developer support because it was just following an already present downward curve.
Although developer resources weren't wasted (most didn't even bother with it); you don't think that by releasing a console that sells like shit doesn't make developers/publishers think twice about supporting their future devices?
Pleeeease.
Not to say that it can't be changed - just sell a shit loads at the start.
You know, kinda like with the Wii.
Lots of developers were all, "Man fuck Nintendo, they made the GameCube."
And then the Wii sold a fucktonne.
So then a bunch of developers/publishers were all, "Oh fuck release something quick before this fad ends!".
Yo.