you raise a bunch of economic issues, but the poster to which i replied simply stated that there was "no where else to go", which is absurd

the rest of your points are dubious. your point B) has been proven false since the launch of the space station...this was one of its apparently initial goals, zero-g bioresearch...except that ended up being replaced with simulating everything in computers with bioinformatics on earth much more easily

C) also has no meaning as we could provide 100% of our solar needs by simply covering a part of any of our major deserts with solar thermal.

http://www.informationisbeautiful.net/2009/surface-area-requ...

D) maybe, but, for a contrived example, if gold is $5000 an ounce, you have to bring it back from mars for less than $5000 an ounce or its a wash

E) completely bogus, no humans could survive long term with constant support from earth, this has been beaten to death