Impossible to get to Mars?

Getting there may not be the problem. Getting there and back alive and well is indeed a problem. Therefore, I think the first missions will be suicide missions. If you complicate matters with the insistence that everybody must come back alive and well, then it might be impossible with the tech we have now.

But someday, not long from now, it will be possible. I think so, because of the rapid advances in robotics. Robots could make a human presence possible. They'll be sent in any case, as Musk said he will send his own robots to Mars. The robots could prepare the war for a short term existence on Mars, but it will take a lot of missions, and a lot of commitment to make the whole thing viable for anything but short term suicide missions. A civilization of over a million people seems like a pipe dream. However, a highly dangerous mission in the near term is likely. Maybe not before the end of the decade, but early in the next.