There's a huge difference between sending a robot probe or small dedicated mining crew with hazard pay to an asteroid and dragging/slinging chunks of precious m

There's a huge difference between sending a robot probe or small dedicated mining crew with hazard pay to an asteroid and dragging/slinging chunks of precious metals sunward, and making a self-sustaining colony on Mars. Like the difference between building an offshore oil-rig (happens a lot) and building a self-sustaining colony on the ocean (never happens), only much moreso.