This is a great point.
Here's the thing: There is nothing wrong with having lots of mutants. There is a LOT wrong with having lots of X-Men. I appreciate that the X-Men are the heroes. I don't want every mutant to know how to be, or even want to be, a hero. We need mutants who need saving and not be one of the extremely few X-Men.
However, it's the problem of editorial that they perpetually continue to age up youth too quickly and force themselves to produce more and more "new generations". Just let let youth be youth for a while. As much fun as it was watching the kids take down Nimrod, they really couldn't go back from there to kids who couldn't control their powers. They tried, like with Elixir developing his onyx skin, and Hellion evolving to too powerful, etc. But then they showed Pixie graduate later, when she was one of the youngest. The original X-Men and the New Mutants got to be young and inexperienced for a very long time.