I am not convinced either. But extensive, reliable scientific information is needed on the resources available and other factors. Extended human expeditions are the best way to get it. Technology is not stagnant and terraforming is not out of the question. But, as I said, this could take centuries. We have to start somewhere.I'm not convinced that we could create a self-sufficient colony anytime soon. The biggest problem is an ecosystem to live in, it's not that we don't have the industry (we don't but that's another issue) but we have a huge lack of understanding as to how ecosystems work that we can't even begin to replicate one. You can spend all the trillions of dollars you like sending the required industry and millions of colonists to Mars but the knowledge just isn't there for us to build an artificial ecoystem for them to live in.