They would require constant supplying, and wouldn't be economically beneficial. We think it's a great idea now, but once it happens, very little will happen for a long time. We won't start a sprawling interstellar empire. The colonies will likely be barely livable and not new and exciting.
When you want to colonize, aren't you just succumbing to materialism?
When you think of space colonization, don't you always think, "We will expand, grow, take our place in the universe!"? Haven't you always loved Sid Meier's Civilization? Don't you love to colonize and conquer? Doesn't it just give you a warm fuzzy feeling inside? If so, you're a materialist.
Space travel is not easy, and it is not cheap. We must consider it with a rational eye and realize that it won't be like all the sci-fi movies, and it's not what we're expecting. Maybe we should consider our earthly problems first, like lack of preparedness for climate change disasters, imbalance of world powers and governments and ideologies, which result in poverty in third world countries. Why spend millions to put hundreds of people on Mars (Mars no less! Why not just the moon? Mars isn't many times better, but it is many times further away!), just to start the expansion of human population, when tens of thousands of people die every day of starvation?
I'm done talking now.
