Don't forget the fate of early Earth colonists
The history of earth colonization includes a lot of early settlements that just didn't work. These settlements rapidly died out, literally in many cases.
We tend to forget that just because Botany Bay is now an upscale part of Sydney and the East Coast of the US is settled and civilized that a couple of hundred years ago things were very different, these places were barely habitable. The only time there was a fortune to be made is if there were natives to exploit (or slaves to be imported and exploited). Without that colonies often failed. Mars doesn't have any life that we could trade with or exploit -- or at least if it did we'd probably be on the losing end - and as a viable place to live it makes the Mojave Desert look positively verdant in comparison (and there's no handy freeway to get you to civilization -- its three months minimum to get anywhere). The only reason for going there is natural curiosity and even that can be handled quite effectively by machines.