The plot is kinda contrived now.
The dilemma of 'should I bring back humans' is null and void if humans aren't even gone. Now the main issue that these humans are having is 'not enough humans' then... What's there to question? Press the button.
In fact, it's kinda invalidated everything else that's happened. those people have ALWAYS been there. Roue has NEVER been the only human, she's just the only one from space that we know about, and she might not even be unique in that regard.