He's not promising it. Despite the optimistic language, its a somewhat-realistic dream that he'd like to do and plans to work on. At least that seems obvious to me.
As far as timelines go, Gwynne Shotwell is in an entirely different class than Elon Musk. If you haven't watched the video, you should, there's some interesting tension going on between her and Elon.
If she says it'll happen in the next X years, I'll put it at a >75% chance of being accurate. If Elon said something like that, i'd put it at 33% chance.