It's cheaper to ship materials to Low Earth Orbit from Mars, than it is to ship those same materials from earth. Can you imagine our current space industry (worth billions of dollars) could be operated from Mars? If there was a settlement on Mars, they could do it for approximately 2/3 of the (fuel) cost of doing it from Earth.

Of course, an industry established at a moon settlement could do it for even less. :-P (1/4)