I’m not sure I get your point. Everything we need is here. Why do we want to be in a different location.
I understand the principle of diversification but we aren’t getting to another star system and being in the asteroid belt isn’t going to really help us if things to seriously wrong in the Sol system.
We don't have to go to other star systems to maintain life off of the planet. We do it now, in a small way, and mine a bif planet (Earth) with a deep gravity well to provide humanity's needs off the planet.
Cheaper to mine those resources from a shallow gravity well asteroid.
We're at early days yet. When the eastern US was still young and pretty open, people still migrated west, even though they had everything they needed where they were.
/johnny
I missed one very important point.
We are losing one resource that can be found on frontiers, even if those frontiers are difficult.
Freedom.
/johnny