Even granted the unlikely premise that relevant materials are more abundant in space than on Earth, the points remain that:

- Good planets are hard to find.

- That the available habitable planetary / surface area is only modestly larger than that of Earth alone, and vastly less hospitable (see: https://xkcd.com/wiki/index.php/1389 https://www.explainxkcd.com/wiki/index.php/1389:_Surface_Are...).

- Costs of space travel in both financial and resource terms would be prohibitive for moving more than a vanishingly small fraction of the human population off-planet.

- Any space colonists would have to first create and then maintain a habitable ecosystem in whatever remote environment they chose to occupy (under conditions which make contemporary epithets of "eco-fascism" appear to descirbe a positively libertarian regime).

And ... given all that, the challenge of living sustainbly on this one small fragile beautiful blue-wite gem we happen to have lucked into coming to existence on will remain for any foreseable future.

Space isn't a get-out-of-jail-free card.