It isn't about human greed to live but his greed to technologically advance and achieve. Humans very well know it isn't easy to adapt on Mars. But he considers it as a challenge to overcome it. Living on another planet in the near future is not necessary scientifically but is necessary psychologically, to aid scientific and technological development.
For me the greatest reason to go to Mars or any other planet or space in general is to find the answer to the age old question of, 'Are we alone in this Universe?'. It seems to me that the reasons for going to space far outweigh the reasons of not going. I was going to make a list but I found it more appropriate to share the attached videos.
However, to live elsewhere other than Earth with the sole intention of greed is disgraceful. Which specific aspects of greed did you have in mind?
https://www.youtube.com/watch?v=aCEvMY3nZoU
https://www.youtube.com/watch?v=plTRdGF-ycs
As per the Religious Scriptures of all major religions, we are not alone in this universe. So, there are aliens, I believe, but I don't find any need to spend billion of dollars just to look out for them while our own earth is in poverty. That money could be spent first for the betterment of the humanity.
The advancements that come from us trying to go into space, or inhabit a planet, benefit everyone. Think of all the things that have already come from the Space Race alone. To quote NASA Administrator Michael Griffin,
"We see the transformative effects of the Space Economy all around us through numerous technologies and life-saving capabilities. We see the Space Economy in the lives saved when advanced breast cancer screening catches tumors in time for treatment, or when a heart defibrillator restores the proper rhythm of a patient's heart..... We see it when weather satellites warn us of coming hurricanes, or when satellites provide information critical to understanding our environment and the effects of climate change. We see it when we use an ATM or pay for gas at the pup with an immediate electronic response via satellite. Technologies developed from exploring space are being used to increase crop yields and to search for good fishing regions at sea."
Space travel affords biological and ecological innovations to be researched and developed. Furthermore, the longing to live on a different planet stems from the human need to constantly surpass the seemingly impossible. The need to overcome and expand.
