Right, the challenge is mainly that the first missions will have to carry a lot of cargo (priced into the cost of sending the crew) and that it'll be easier to

Right, the challenge is mainly that the first missions will have to carry a lot of cargo (priced into the cost of sending the crew) and that it'll be easier to bear the cost of development and construction if the early missions have a higher price. Even if the cost for the first few trips was $50 million per person, there'd be no shortage at all of people who would be paid for by governments or organizations with that kind of money. Might as well use it, and apply these funds to expanding the program. Full reusability is really the essential part of this system - you can't afford to throw away any stage of a rocket this big. Fortunately, the larger the vehicle, the easier reusability tends to be (up to a point of course).