I love what Musk is doing, but both of his current engineering successes---Space X and Tesla---involve building well-understood vehicles, just faster and at less cost than competitors. Doing entirely novel projects like a manned mission to Mars or some new kind of mass transportation system are orders of magnitude more difficult and uncertain, and I think he's grossly underestimating the time and cost for either of his more ambitious new goals. I'd like to see him make plain vanilla space transportation and electric cars into business successes comparable to PayPal before he moves on to Mars and Hyperloop.
I also hope he'll be making lots of money on Tesla and SpaceX. I don't know whether he'll be able to make going to Mars pay, but the money he'll spend will do the market some good.
I would like to see him do both. Even if the Mars stuff doesn't work out perfectly on his ambitious timeline SpaceX devoting resources to pushing the boundaries as well as refining the well known processes is going to create more innovation in the long run.
I would too, but in terms of immediate impact Tesla will have a greater social and economic significance for the planet than the Mars mission, and the company is really only getting started. I would hate to see Musk get bored with it and move on to a new toy while Tesla fails for lack of leadership.
