I think you mean, “it does matter”, since you describe different outcomes. Even in the case where those were pathogens, they may subsequently lose the competiti

I think you mean, “it does matter”, since you describe different outcomes. Even in the case where those were pathogens, they may subsequently lose the competitive pressure to be good at fighting. Then when they re-encounter a robust environment, they may be totally annihilated. In certain types of bio research, we now have to protect the species from humans, rather than the reverse, since they have been without that competitive pressure for so long and become optimized instead for growth and production.