Elon's a funny animal. Most hype artists are full of shit and never deliver anything. Elon is full of shit but then ends up actually delivering something rather amazing-- but maybe not quite as amazing as promised and never as quickly.
In /r/spacex they joke about "Elon time." Take "Elon years" and triple them.
Of course this is typical for engineers and Elon is an engineer. I do it too. "Oh this will just take a few weeks" == months later...