There are domains in which expertise is not possible. Stock picking and horse selections are two good example. And in long-term political strategic forecasting, it’s been shown that experts are just not better than a dice-throwing monkey.

Let's be more realistic.

An expert in any field will have an advantage over a mug person. But neither the expert nor the mug person can be sure of when or where his next winner will come from. But the expert will just have a better guess and advantage. Unless of course you happen to be in the right place at the right time and the right genuine people you associate with.