Yeah, SpaceX is doing good work, being economical like many other space agencies and yet being able to land back the stage 1 booster. Of course, they haven't reused even one yet, and have not studied the effects of multiple reuses.

But going from this to imagining a space taxi and a space settlement? There is so much work that needs done first, effect of radiation on people? Effect of lower gravity? Effect of high concentration of heavy metals on plant life? Recycling everything? Making propellant on Mars? And so much more, he just hand waives it saying that is easy, all their idea relied on was reusing their booster 1000 times, even when they have not reused it once! If I wanted science fiction (not that I think it is impossible), I would read a book.

It's really like the Wright brothers doing their first test flight, and then imagining a commercial airline system, complete with Boeing 777, airports and hell even SR71 Blackbird. It's just too far off, and feels like a sci-fi con. Plus you can see what kind of people this thinking attracts, like that idiot who thinks that Burning man is what mars is going to be like, completely ignoring the thin atmosphere, lack of gravity, cold temperatures, and all its' effect on humans, plant and building materials.

I think your example actually harms your argument. The SR-71 is a nice plane, and certainly much more advanced than the Wright Flyer, but it is completely outclassed by the Saturn V. The space technology is much more complex, and much more energetic, and has far tighter tolerances, and less room for failure. You should have been making this same argument in the early sixties. Right now we do have the technology, the engines, the fuel, the deep-space communications network. We need to scale up the engines to rival the power of God Almighty, but we don't need new physics to do so.

Musk is pointing out, correctly, that this is possible with existing rocket technology -- at least the transportation. Keeping people alive once they're there is apparently somebody else's problem, but until we have the materials science for a space elevator, an obscenely heavy lift vehicle will probably have to do. Ultimately he's going to be asking a lot of people to climb on top of a monstrous Engine and hope that it explodes correctly, and I hope that his conscience is clear when that day dawns. Probably you are right that we're going to have a hell of a time keeping people alive on Mars, but we seem to have a tough time of that here as well.

This is not science fiction. There is no new physics required, just some fiendishly difficult engineering challenges. The Wright Brothers were able to build their plane because there was nothing physically stopping them. They had the scientific knowledge and the dedication, and everything else followed. Really it's not that people -- even Presidents -- haven't been talking about doing this and working on details and preliminaries for decades. This is news precisely because it's not science fiction. This time, it could actually happen.

I think there are some false equivalencies in here. There are real serious challenges to be overcome, especially (as you say) dealing with the radiation exposure over >= 3 months in deep space, and we've seen the serious health issues Apollo astronauts have suffered from after enduring the same sort of exposure for a comparatively short time. But overall, the science and engineering are largely in place; to do this it will take scaling, integration, and refinement all on a massive scale, but it really isn't like e.g. going from the Wright flyer to SR-71. The latter was unimaginable back in the day of the former, which simply isn't the case for SpaceX's plan or it would be getting a lot more flak from real experts than it apparently has been (though, let's be honest, SpaceX are the real experts now).

And, again, nobody's saying it's anything other than a long shot, not even Musk himself. But a lot of people seem to be pooh-poohing it for bad reasons. For instance, the awful quality of the audience at the Q&A does not in reality tell us anything about SpaceX's ability to execute on some or all of this plan. In fact, I think Musk was ready for much more challenging questions than he ended up receiving (how could he not have been?)

Where in the recording did he say it was easy?

And where in the recording did he say it was going to be hard?