As much as I'd like to believe otherwise, I just don't see much chance for a manned Mars mission in my lifetime and I'm only 44. Commercial companies exist to make a profit. Unless one of the robotic probes finds something extremely valuable on Mars, I just don't see a private company making the trip.

As for government, how many times have people in Congress tried to kill the ISS and how close have some of those votes been? A manned Mars mission will take many years to assemble. That means building and maintaining political support for some really big budget allocations. Sorry, but I just don't see it happening. We might be able to fund a Mars mission at a couple billion a year after we finish paying for the ISS. The question is, will we ever be finished paying for the ISS? However, that would mean we'd need international partners to help pay for the rest. The longer you drag out the development cycle, the more it'll cost. The days of Apollo Era "waste anything but time" funding are long over, and just because some politician wants to lead doesn't mean that people will follow. Whether it's a lingering post-Vietnam or Watergate or "I didn't have sex with that woman" malise, few people look up to politicians as people worthy of respect anymore.