Maybe we don't see them because they aren't as numerous, because they aren't interested in spreading out. Maybe the "drive" to spread out and colonize the univ

Maybe we don't see them because they aren't as numerous, because they aren't interested in spreading out. Maybe the "drive" to spread out and colonize the universe or the cultures that would encourage that frame of thought are linked to a propensity to wage war or other some other counterproductive behavior that results in extinction before achieving the ability to colonize the stars.