Just to throw a hand grenade into the discussion - I honestly don't think it matters if people go to Mars - at least not right now. People can't live on Mars. Or on the Moon. Or anywhere else that we know of except Earth.

The distance between here and where ever the hell else in the universe people can live is so far, that in the absolute best case scenario it would take many, many, many times longer than written history to reach such a place using any propulsion system that we can currently imagine constructing.

Its a total fantasy. In order to make it a reality you need one of three things:

1. New physics.
2. Artificial BioSpheres that are sustainable for multiple generations.
3. Post-Humans.

You're not going to find any of these things on Mars. The first may not exist at all. The second is enormously risky, expensive, and far fetched. We're going to build cities under the sea long before we know how to build sustainable space craft that can last thousands of years, and we're aren't working on the former as far as I know. The later seems like the most likely bet.

We should be focusing on genetics and robotics - not space craft.

We'll build things with human like intelligence that can live comfortably in alien environments before we'll build vessels that enable humans to live comfortably in those same environments.

Who cares if people go to Mars?