I think this point is by far the easiest one to address. Historically, there have always been people willing to do dangerous things (ie exploring the Arctic / Antarctica). I don't think you'd have any trouble finding people willing to give up their Earth lifestyle for a chance to explore the "frontier" even with the knowledge that they couldn't come back.
I doubt many people are willing to live the entirety of their lives in constant danger and constrained resources. And even fewer of those people will have the skills needed to run a complex technological society (and you will need a lot of technology to survive on Mars).
Yet a very large majority of North America is descended from people who did exactly that.
And those, who settled, came here looking for a better life, which should tell you about the conditions they were coming from.
And that is especially true for the many of the early colonists.
But the most important thing: we no longer live in the 1500-1600s which is a very important factor overlooked by everyone breathlessly talking about enduring hardships on Mars