The right idea was in front of the eyes of the right person at the right time.
The idea is a staple of light sci-fi, but apparently has not crossed the desk of the right agents in the right mood.
So: luck.
Which is wildly underestimated as a cause of success.
I look on things like talent as necessary but not sufficient causes of success.
For my fuller view: http://chester.id.au/2012/03/02/does-leadership-matter/
The key is that the Internet enables a giant magnifying glass on everyone. This could have died out, but now it has a chance to live.
There are still great ideas dying in coffee shops. They're just dying on reddit too.
And _that_ is caused by a qualitative change - physical proximity has become way less important.
It used to be that you needed to convince Ugg, the big man of your tribe. Then you had to travel to Babylon -- or instead send clay tablets. Then you could be heard in Alexandria from Rome if papyrus copies of your words were transcribed and shipped. Eventually the printing press, telegraph and regular steam train schedules meant information about your speech in Paris could be news in Berlin in hours.
Today, in a few seconds, I put my hypothesis on the nature of the internet to a few hundred strangers scattered across the globe.
That's what I mean by a quantitative change. At each step, the number of people you could potentially reach has increased; the cost of doing so has fallen. I don't see it as a qualitative change, though, I see it as a series of smaller stepwise improvements.
An exaggerated comment, I think. There's a lot more content out there on the net, there's no way all content gets an equal share of attention - you end up with a lot of concentration and a greater amount of darkness. Actually every little thing you post and share is diluted in enormous mass of information. Even viral videos are usually obscure for several years before someone influential happens to find them and relink them.
It may have been true at the earliest stages of the web, but in 2012, it's pretty hard to stand out on the web and to benefit from the "giant magnifying glass" you mention.
Success ∝ Ability * (Hard Work)^2 * Sqrt(Luck)
In a world without Reddit, the role of luck would have been even greater. What are the odds that, had this guy simply written his ideas into a book or screenplay and tried to send it out to agents, he'd ever have gotten noticed? Or even read? Having worked in that world before, let me tell you: pretty close to zero. Absent any connections to the film world, it's almost impossible to break in.
The fact is, Reddit expanded the range of the sets "right place" and "right time." Without it, those sets would have been infinitessimals. People here like to talk of expanding one's "luck surface area," and to me, this is a perfect example of that concept.
And then, after you make that one in a million deal off some crazy-good pitch to the right executive, there's no guarantee that it will ever get shot. There are many writers in hollywood that have sold dozens of scripts and only ever had one or two get produced.
(I'm not saying you are wrong, I just think this is a paltry excuse.)