Colonies on Mars only 12 to 15 years away, Elon Musk says

Elon Musk, who helped launch PayPal, Tesla Motors and most recently SpaceX, is pretty dang serious about getting to Mars. Before Curiosity, colonies on Mars were knocked back to the 2030s — or beyond, even. Now? We may only have to wait "12 to 15 years."
In his vision of colonizing Mars, musk isn’t looking to send highly trained astronauts to perform science and return to Earth. He’s looking to send people like you and me, at a price a corporation could subsidize.
Speaking on ABC’s "Nightline," Musk said:
"I’m confident at this point that it can be done. I think we’ll be able to send, probably, the first people to Mars in roughly 12 to 15 years. That’s my estimate… We know it’s possible to get there. You would be moving to Mars, so a round trip ticket, it has to be no more than half a million dollars, so roughly, a middle-class house in California, and at this point, I would say, I know it’s possible.
I certainly don’t have $500,000 to blow, and chances are you don’t, either. That means the first civilians to go to Mars as colonists would be sent by governments, grants and corporations. Because SpaceX is a commercial spaceflight company, it wouldn’t necessarily have to only enable NASA missions to Mars. Ideally, SpaceX would be able to use reusable rockets to make regular trips to and from Mars.
Musk’s vision is larger than just spaceflight as a business. Again, from the "Nightline" interview: "Mars is the only place in the solar system where it’s possible for life to become multi-planetarian. We could make Mars like Earth… it’s more than our life raft, it’s like backing up the biosphere."
What Musk is referring to when he says "life raft" is the idea that having only one colonized planet puts human civilization at risk. With a second planet, say, humanity would survive an extinction event on Earth and, as the thought goes, prove that we’re smarter than the dinosaurs. So far, that’s a theory and not a law.
We’ll end with a little more from Musk:
"I think it would be the most difficult thing that humanity has ever tried to do. The Earth has been around for four billion years and in all that time, it’s been confined to one planet. That’s a long time… And now for the first time in almost four billion years, it’s been possible — very difficult, but possible — for life to extend to another planet. if we can take advantage of that opportunity, who knows how long that window will be open?"