You could well be right, human nature stays the same, or at least changes so slowly that we can't perceive it. So that could be a valid reason as to why there will be money, soldiers and advertising agencies on Mars.

However the process of terraforming Mars will happen very slowly, so that means that there will definitely be a time on the planet whereby those things are not available. No soldiers because there's no one to fight and nothing to defend. No money because there's nothing to buy, ditto advertising agencies.

Therefore I don't think it's too much of a leap to think that once a status quo of no money has been established. The people living there might want to keep that status quo as it is.

Also if you take a look at the Elon Musk video, he explains how SpaceX is recouping its investment by taking up comms satellites and repair missions to the ISS. Hence he will have little or no need to try and recoup the investment from Mars itself.

We (or rather our Grandchildren) will see :-)

Cg