Because the election is far from over.
That does not work in a criminal court. You kind of need an actual crime. And proof of that crime. More than "I believe this to be true." No court in this land will take a case where the charge is "Can you see if they committed crime?"
No, that's your job as the person bringing the case.
But, for betting purposes, I too would hold off with paying out until everything is properly finalized. What if one of the candidates suddenly keels or withdraws before the changeover? If the betting company has to reverse course, they could end up in court and end up paying tons.