Not to be "that guy," but I think the real reason we'll never colonize Mars is simply that we're going to run out of time. Climate collapse and/or nuclear war will probably set in long before we have the technology or wherewithal to terraform a planet millions of miles away. We may be only a decade or two from severe environmental catastrophe, which makes the prospect of Mars colonization pretty far-fetched at best.

To be clear, I don't think studying this is a waste of time. On the off chance that we get there, that'll be great (setting aside the concerns of this article of course). It just gives me a sense of a terminally ill person planning their retirement. Sorry to be the downer here.