During main gameplay your resource extraction and expansion is driven mainly by the sink of ‘research’ - turn resources into science, science into unlocks.
Additionally, biters eat bullets, and occasionally factory parts that need replacing.
Other than that the main sink for all your resource gathering is just ‘more factory’ of course.
The end game resource sink of ‘space rockets’ just never felt to me like a very satisfying thing to shoot for - though getting to the point where you can just expand onto a new mineral patch and reliably deploy blueprints that turn it into rockets is pretty cool, I’ll admit.
But there’s a part of me that is left slightly unsatisfied by the fact that we can’t reach sustainability, and we aren’t getting anything for all the resources we process.
Give me a little population of friendly alien creatures (who biters prey on) and make my goal to maximize their population, perhaps. I don’t know.