To be honest, the surface of Mars has more in common with the land surface of earth than it does the floor of Earth's oceans.
Sure. But the problem isn't that the Martian surface is so inhospitable to human life. It's that it's
really, really far away. And the cost of moving materials to Mars is enormous. And we don't have a whole lot of vehicles with which to do that (or, at this point, any). And cost of creating said vehicles is enormous. And we have no practical experience trying to maintain any sort of human habitation beyond Earth orbit (and even the ones we have are in no sense permanent).
None of those obstacles are insurmountable. But they're not the kind of thing you can fund by selling broadcast rights, tee-shirts, and coffee mugs.
Without the direct backing of powerful nation-states, flush with resources, and capable of massive borrowing/fiating currency into existence, a project of this scale is impossible. Frankly, even dealing on the nation-state level, in terms of mustering the public support for such a big project, we'd need another a Cold War, to, umm, redirect national priorities on the required scale.
Which isn't to say the Mars Project doesn't have it's uses. Considered as a piece of advocacy of human spaceflight, it's kinda cool. And considered as a piece of
marketing for SpaceX's much more modest
business of low-Earth orbit cargo hauling, it's kinda brilliant.