Yes, ND can magically bring new Siblings to serve the plot, but they do not have another living surgeon in all of USA, when the research is already done and operating procedure is left on the brain of Ellie. C'mon the whole focus of ND was political pandering to represent everyone. I guess Neil woke up on the wrong side of history, because during development of Last of Us 2, this woke culture was on the rise, but since then, the alt-right across the world are fighting back. That is the reason why this game is getting so much hate.