Speaking from my own experience, I think there is a certain percentage of creative people that simply do not want to consume fiction and the related. We are driven to write it, and I think that drive makes reading it so much less fulfilling. Like, why read a story, when I can make it up my own way, and make things happen the way I want them to? Especially when we have busy lives and limited time to do what we want. That said, we must be a small group, because everyone I know spends their time happily watching some sort of video entertainment or reading fiction. So I guess us writers are safe. There will always be plenty of consumers so long as they can find us :)
The comparison to porn was really interesting to me. I had never thought of the comparison between a plot and sex. All this instant gratification out there might be training us to want to fastforward to the good parts, meanwhile, all women know the ending never goes so well without a great deal of content leading up to it ;)