Colonies on Mars are what drove the founding of SpaceX. Elon was looking up NASA's plans about sending humans to Mars and found that they simply didn't exist. He wanted to send a greenhouse to Mars while streaming its growth to get people inspired and thinking big again. NASA wasn't interested, Russia wanted too much $$$, so SpaceX was born. A colony doesn't mean you live there forever - it simply means a permanent human establishment. Some people will want to go back to Earth, some will want to stay on Mars indefinitely.
This is a big part of their obsession with lowering costs to space. When the launch costs are not such a huge economic factor, you have much greater leverage with doing things like building, resupplying, or even engaging in interplanetary commerce.
This is a big part of their obsession with lowering costs to space. When the launch costs are not such a huge economic factor, you have much greater leverage with doing things like building, resupplying, or even engaging in interplanetary commerce.