But it is possible that you can never win

The single most difficult concept to grasp in probability theory is that of calculating the probability of success. It requires a way of thinking that is "counter intuitive", that is to say, it produces conclusions that cannot be arrived at by applying common sense.

In the doubling up strategy of the roulette system, the weakness was that there was a very real chance of failure. Averaging out over many players, one player in fourteen would fail. Similarly, the man dividing his time between six projects, then failing and trying six more, then failing again and choosing another six, can never be certain that he will ever succeed - however many times he tries. Just as it is possible for an exceptionally large run of reds to occur at some time during the history of a roulette wheel, so, it is possible for even the smartest business person in the world to have such a bad run of luck that he or she never succeeds.

It is this very real possibility of never succeeding that cause most people to shy away from risk, particularly if it involves the possibility of losing all of their money, their job or their health. Game theory deals with this problem by using compromise.