To a certain extent, I agree with you. I do think we tend to think campaigns matter far more than they do and that the economic/societal context of each election make a far bigger difference than we typically recognize.
However, we also have to say that Trump has, over 3 elections spanning almost 10 years, done an incredible job connecting with working class voters and pulling them into his base. He activated a whole lot of new working class voters in 2016 and they have now formed an important part of his base. And in this election he very much pulled Latino voters, especially Latino men, to him and away from Dems.
We should be careful to not attribute too much to campaign brilliance, but we also have to observe the things that campaigns do that are atypically effective.