All of my examples were talking about real life to illustrate a point. Of course you can have a fictional genius scientist still single handedly making break throughs in a sci fi setting. In fact, that's pretty common. The point is that the same reason that sort of thing doesn't happen anymore in real life is also what makes taking advantage of cool sci-fi stuff like mechs, cybernetics, and space travel that isn't just reflavored boats/automobiles difficult without involving decently large organizations.