You nailed it: Infrastructure
I want to see humans on Mars as much as anyone, but I also want humans to go to the Moon, the NEOs, the asteroid belt, Callisto and beyond. The MS folks just can't get out of their Mars Direct mentality. Yes, Mars is probably the most human-friendly alien planet in the solar system, but it's NOT JUST ABOUT MARS. It's about establishing a human presence throughout the entire solar system. Infrastructure in cis-lunar space is far more important to that goal than a mad dash flags and footprints mission to Mars.
