But why should that be? If you're a scientist, you are dependent on getting funding to do experiments, and the experiment showing something interesting. Neither of these things is very connected to intelligence, beyond that low IQ people will not be likely to get to the start line.
If you're an entrepreneur, you also have to do a bunch of things that are more social than smarts. Basically your life is going around meeting people and getting them to either invest or build something or buy something. Is it useful to be smart? Sure. But it isn't as useful as, say, having the right connections from school, or a family with a sensible budget so you can concentrate on building rather than finding food.
Pretty much the only area where being super smart works is pure maths, and even there you really want to be born in the parts of the world where the economy can support a young person on that path.
Then there's the transmission to suit your engine. A super smart person still needs to be mature enough to consume the intellectual royal jelly that develops them towards where they will make the greatest contribution. You won't just know what to do just because you're smart, you need to be shown what the interesting problems are. You need to have motivation, and motivation is often what you actually see when you meet someone impressive.
The way I think of it, the smart and useful people are plenty. Courses are taught so that universities can get a sensible number of people through some amount of content. Being smarter than your average student at a prestigious college is nice, but it mostly buys you some free time. Being at the cutoff is terribly stressful, but that guy is still pretty accomplished and useful for most things that we consider elite.