Earlier quoted context omitted.
The best criticism I can come up with is that 538 probably doesn't do a sufficient job of explaining to its audience that their published probabilities are predictions for what would happen if the event occurred today . This seems to be one of Taleb's (and others') criticisms of their predictions: that they don't consider the probability of major unexpected events occurring between now and the event (like an athlete…
That seems like a pretty big difference to gloss over. Why are they publishing probabilities for if the event were to happen today? The event isn't happening today!
538's forecasts, especially far from election day, are for the newspaper consumer. They provide insight into current political dynamics, and a quantitative look at how people view policy, the economy, where current fundraising is at, etc. in a single concise number that can serve as the basis for further discussion and analysis. They however aren't useful for the sportsbook consumer, because they don't account for the practically innumerable "unknown unknowns" that will occur between now and election day (scandals, terrorist attacks, fluctuations in the economy, flubs on the campaign trail, external activist efforts gaining traction). If they did account for all that uncertainty, then the predictions consistently be near 50-50 for the majority of the race, which not only is still uninteresting for the sportsbook types, but also means you no longer are providing value to the newspaper types.
Its important to point out that, over time, the predictions become applicable to both readers. As election day nears, the number of "unknown unknowns" decreases, and a prediction for "what would happen if an election were held today" and "what will happen on election day" converges. So up until the few months and weeks leading up to election day, the predictions should be taken more as commentary, and then perceived as serious indications of what will occur closer to election day.