As I said, messaging and candidate charisma is the primary driver. Biden was always a mediocre communicator. The octogenarian version of Biden was a uniquely dreadful communicator, incapable of articulating the kind of message that would move votes. Harris had a double challenge of digging out of the hole Biden left her and the party in....and the miserable identity crisis the Democrats have found themselves in during the Trump era where they had to be instructed by Gretchen Whitmer to talk about the economy in Michigan against their instincts of avoiding conflict with the managerial class who they felt dependent upon for victory.