He was talking about his personal perception of the future not the technicalities of existence. Jesus the level of poindexter in even philosophical pleasantries is suffocating on HN.
I mean, they were right. Quality of life improved for the European colonizing nations. Not so much for the natives, but presumably we're not going to run into anyone already on mars.
There is no 'green grass' on Mars, literally or metaphorically. There isn't even any 'air'.