Got that, and it's fascinating. What I didn't expect was the youthful entrepreneur channeling Robert Heinlein and other 1950s science fiction authors on the post-earth destiny of the human race.
Musk also runs SpaceX, a pioneer in commercial spaceflight. He's got a contract to deliver eight loads of cargo to the International Space Station, so SpaceX is an actual business, not some stary-eyed dream.
Those classic sci-fi writers defined adulthood for mankind as not being bound to a single planet, just a single asteroid strike away from extinction. Musk does too.
His observation was a throwaway line before resuming talk of Tesla. But compared to insuring human survival, taking on the established auto industry isn't so tough.