Many people say that a Mars colony is economically unsustainable as goods from Earth will be considerably cheaper for the foreseeable future and Mars won't have anything to trade in return. This got me thinking, that due to Mars' lower gravity and lower density atmosphere launching satellites into Earth orbit might be cheaper to do from Mars rather then from Earth, despite the need for a much longer journey. Is this correct from the point of view of orbital mechanics?
If feasible this would also require the satellites to be manufactured on Mars. What sort of level of development (colony size, equipment) would be needed on the surface of Mars before the Martian satellite industry can be cost competitive with the Terran one?
Are there any other examples of industries where this could be the case?