Does Adams have a track record at predicting this sort of thing? I am not aware of any instances he's said "here is a master persuader trying to do X, they will succeed" and them having failed, but I can't remember more than one instance of him saying that and it being correct (and I don't remember the specifics), but I don't follow Adams closely enough to have a good count.

I think that Adams is raising the sort of challenge that Silver is weakest against: Trump's tactics are a "black swan" in the technical sense that no candidate in Silver's dataset has run with a similar methodology. That Silver thinks Herman Cain's campaign is the right reference class for Trump's campaign seems to me like a very strong argument for Silver not getting what's going on.