This makes it seem like there was a quota of people who like the general crux of the campaign, that quota was reached, and now they need to move on to the next groups. But I don't think that is how elections work. She also of course risks losing the group she initially got massive buy in from.

Many voters do not have fixed views on the election and they only are paying attention from afar. And I don't see how those remaining people to be persuaded are going to be more persuaded by boring middle of the road stuff.