Has this same exact thing not been predicted every decade for the last several centuries?
I could type pages and pages on this topic, but I'm going to try to keep it short.
No single report ever made me take this opinion. It was years of reading, observing, and thinking on a wide variety of subjects as diverse as, though not inclusive to, sociology, geography, philosophy, physics, and history. It's a possible future I've seen coming for a long time. Granted, I didn't create a complex mathematical model like NASA did, but the fact that they have now made one confirms a lot of what I had thought could happen over the years might happen in our near future.
Over the last several centuries, there weren't 7 billion people overpopulating this planet with unsustainable lifestyles. There was no global economy with the accompanying global supply chain that civilization relied on to keep up and running. There was no advanced technology that caused us to be reliant on, and thus strip, the planet's resources and change the climate enough to threaten our ecosystem. There were no weapons that could destroy the ability for intelligent life to flourish on this planet.
The sociological aspects, in this case concentration of wealth by an elite class, combined with my strong belief in cynicism and the difficulty of getting any large group of people to work towards a common goal and this perfect storm they talk about becomes a distinct possibility. I personally believe that anyone who doesn't see this as a distinct possibility is either uninformed, willfully ignorant, or just plain intellectually incapable of thinking on such a "big picture" level.
And just to make it clear, this is not the future I want to see. I'm not trying to fulfill some pessimistic fantasy I have in my head. It's the future I've dreaded since my mid 20's, and it seems to be coming closer to reality year by year.
Edit: For clarification, I'm using cynicism in this case as the tendency to believe that people act in their own self-interest.