This isn't actually true. The probability of winning is based on aggregation of regional probabilities. The same national vote probability distribution can lead to very, very, different election probability distributions due to regional variation. The electoral college essentially guarantees that the national probability distribution is worthless for actually predicting who will be President.
If candidate B then wins, it does not mean that our analysis was "proved to be [in]correct". By itself, it doesn't actually say anything about the quality of our analysis. After all, we explicitly pointed out that this was a possibility, and it would be strange to argue "your analysis said this might happen, and then it did, so your analysis was incorrect". There's just not enough information to draw any conclusions.
How about 100 times? 10 times? 2 times?
At what point does evidence cease to 'say anything about the quality of our analysis'? The answer is never. Every datapoint can be used to update your priors according to bayesian statistics.
Especially for someone who titles them-self "Chief Scientist"
Aren't regional probabilities just conditions on the national distribution? Building the national Presidential election distribution from the conditioned distributions versus just using the sampled national distribution is bayesian statistics.
>The probability of winning is based on the popular support for a candidate
This was the argument you made. And I don't see how this is Bayesian vs frequency when all I am saying is that the same national popular vote distribution can have large variance in regional conditional distributions which leads to large variance in election outcome distribution due to the electoral college.
Sounds pretty bayesian to me.