Through Makurze I found this article that asks the question "Why is 3D printing rising so fast?" The article does a good job of explaining the history of 3D printing to this point, but it doesn't answering the question it asks very well in my opinion. The article suggests that the rise of 3D printing is "just because it is becoming affordable." Allow me to respectfully disagree and suggest that the reason is it went "viral" because we wanted to believe.
The biggest reason for 3D printing's rise was the RepRap project. Maybe you didn't hear about 3D printing from the RepRap project, but the start of the chain of people that led up to you hearing it started with RepRap. When I first saw the RepRap all I was able to hear was that for a couple of hundred dollars I could have a box in my home that would spit out anything I could imagine tirelessly and flawlessly. This was a lie, but it was a lie that was so pleasing that in my excitement I told others that here was this project that for a couple of hundred dollars could make anything, including copies of itself. And they told others, and they told others and eventually someone told you. I don't think anyone intentionally lied to any of us, I think our brains just cherry picked the best parts about what we were hearing and they added up to this wonderful fiction.
Trailing behind the viral spread of this false idea the reality crept in. It would probably be at least $1000, it wasn't very reliable, it was dreadfully slow when it did work, and the parts it makes aren't very smooth detailed, or big. And taking an idea from design to reality involved, first of all, design, which is hard, and secondly a lot of strange processing before it can be fed into the machine. But the dream was so desirable and we were so vested in it that we kept believing and kept following the "one day" when the dream would be reality.
I think that's the reason why every time Makerbot's next machine turns out more expensive I feel a little loss. This is suppose to become more affordable, not less. But then some other idealistic newcomer enters the market with a great printer that's cheaper and a little hope blossoms in me again. We're not there yet but one day someone will make that magic machine that can take an STL and quickly print it without any strange processing and only costs $300. And it's that hope, that desire, that dream that is the reason why 3D printing is rising so fast.
Just to be clear, what we have already is pretty darn awesome and it's making some thing possible that we're possible 1 year ago. It may not be the dream we promised our self, but it is super cool nonetheless.