The point is that the reason isn't justified because the person correctly predicted an outcome. The reason is justified because the reason was based on true fact and is demonstrably capable of causing the effect.
Now if the Colts win the super bowl despite having worse talent because the opposing Saints team members all got drunk the night before and were playing with hangovers, then you would be justified in saying the predictor was lucky. It's not enough to say someone could have been lucky and then dismiss them. You should show they were lucky or accept they were correct in their reasoning.
It should be pointed out that with Aristotelian logic, that is false. "Previously I said X will happen because of Y, and X happened." is basically "Y implies X; X is true; therefore Y".
Nevertheless, it is true that if a person makes a claim that something will happen for a given reason, gives plausible logical reasons, that we have priors that also indicate the causative connection is sound, and the prediction ultimately comes true, we should not just ignore it. We may not be justified in using Aristotelian logic to conclude with 100% confidence the person's reasoning was correct, but we are justified in taking it into account and concluding that there is some reason to believe this person, who made a prediction contrary to many people's other beliefs, may in fact have something.
After all, if you're not going to listen to people who make accurate predictions with plausible reasons used for their predictions, you can just give up on science right now, because that's all it is.
And I think you're making a mistake to equate ball games with debt markets. The fortunes in ball games can quickly and unpredictably turn. Debt doesn't work that way. If many people on low income take out mortgages on a teaser rate that goes up two years later to levels they cannot afford unless house prices keep rising at historically exceptional rates so they can remortgage, you know you're going to be in trouble eventually.