The undercurrent of dissatisfaction which led to his popularity was already there. And has been for decades. Do you blame the drought, the dry kindling, or the match?

You don't get the wildfire without all three, and anyone paying attention can observe the looming danger and the inevitability of ignition. Who lights the match matters. But is only a small part of the contributing circumstances.

I assign a fair portion of the blame to a consciously self-serving, opportunistic match, yes.

Trump is at least in part directly responsible for said undercurrent of dissatisfaction. He's been part of the wealthy scammer class for decades, providing the drought, kindling and matches. The fact that he's the most visible of the bunch and popular thanks to being on TV doesn't remove his deep connections to the root cause.

The wealthy have been manufacturing these issues for decades now by buying up the entire media apparatus and gutting systems to the bone so that they can squeeze out a bit more blood to drink.