“In the cultural sphere, the hybrids are more robusts than pure breeds.”
In: Interface Culture : How New Technology Transforms the Way We Create and Communicate.
Game genres fade away at the same speed they come into the mainstream. As put by Daniel Cook, the saturation of the market with a particular genre will often kill it. Will that happens to nongames? Maybe.
Elektroplankton deserved its own Nintendo DS limited edition, Nintendogs and Animal Crossing DS apparently are going to sell well... I would say there is a 'nongaming boom' approaching. From a developer point of view, I would rather explore the nongames market than try to develop for the upcoming next-gen of consoles (less cost and possibly more creativity). So we might see the market flooded with nongames - and the death of the genre - quite soon. But maybe not.
Maybe 'nongames' are something closer to a subgenre, a feature. Maybe it should be always mixed with, or inside, other genres. And that is where Steven Johnson's 'hybrid' theory fits: This characteristic could give nongames a flexibility that would extend its life as a genre. If that is what it is.