They're not really mutually exclusive problems though. Especially homelessness where the issue isn't technical so much as will. Other issues like say global warming may dovetail rather well with settling Mars. Our rovers run on solar power and RTGs. Which is fine for something small. But to even think of safely living on Mars. We're going to need to figure out how to run power intensive equipment like bulldozers and excavators. That means we'll need to deal with some of the more thorny issues related to energy and global warming.