You're suggesting a counterfactual trade with them?

Perhaps that could be made to work; I don't understand those well. It doesn't matter to my main point: even if you do make something like that work, it only changes what you'd do once you run into aliens with which the trade works (you'd be more likely to help them out and grant them part of your infrastructure or the resources it produces). Leaving all those stars on to burn through resources without doing anything useful is just wasteful; you'd turn them off, regardless of how exactly you deal with aliens. In addition, the aliens may still have birthing problems that they could really use help with; you wouldn't leave them to face those alone if you made it through that phase first.