While this is all fun and everything, the assumptions underlying all of this are:

1) There are no hostile organisms on Mars.

2) People can thrive in 1/3 Earth gravity for long periods of time.

3) A way (or ways) can be found to counter the severe radiation which bathes the surface of Mars.

While one can speculate all one wants, there is simply not enough information available now to provide conclusive answers to any of these yet.

Finally, another assumption is that the societies of the Earth will be in sufficient shape to undertake the effort. This is yet another BIG assumption.

And on this assumption, as for all of the assumptions above, we simply don't have enough data yet to arrive at an answer.

My apologies for the SCREAMING CAPITALS, but it seems that that is what it takes to wake some of you folks up.

ep