In addition to the other response (risks), the economy is not a stable homogeneous field. None of the economy is a stable homogeneous field. Instead it's a bunc

In addition to the other response (risks), the economy is not a stable homogeneous field. None of the economy is a stable homogeneous field. Instead it's a bunch of discrete individuals living their life and each focusing on just a few things. And this goes both ways. For a competitor to form requires one small team of founders who are insane enough (in a good way) to believe they should try it, and a funding source that's ready to take the gamble on/with them. So you might get a fantastically successful company "out of nowhere" (Amazon, say). Or you might get a field where nobody is at the moment on hand to try it. Or several do try it and fail silently and you never hear of them. They are individuals, not some mathematical process. See also, even "efficient market" does not refer to THAT.