Science doesn’t really happen if we continually ask “Why do this?” Science happens when we ask “Why not do this?”

If we want to be a galactic civilization, we must first learn to live on worlds otherwise uninhabitable. The engineering challenges we must overcome to make that happen will give us the knowledge and experience we need to make it possible to expand past our solar system. This is a very long term advancent, and what we do today is what our offspring will do with ease.

Other than political roadblocks, the final roadblock to galactic expansion is FTL travel. We have theories on how to make it possible, but we are limited to the engineering and knowledge of our time now. Far future generations will be the ones to discover if and how to make it possible, but they need the foundational knowledge and experience of how to live in space.