If you look at the election prediction history graph on Nate Silver’s substack, you see an upwards trajectory for Trump/Vance ever since the vice-presidential debate. That was also when the “Republicans are weird” narrative that was working so well for Harris/Walz abruptly left the discourse. And I believe that what happened was that Republicans who were embarrassed by Vance as well as Trump had a moment like you describe where he suddenly didn’t seem so unrelatable and that right there sunk the Dems… as much as it pains me to admit it, because I’d much rather have a party that wins on the issues and communicates clearly how insane and risky it was to vote for literal autocracy, the Harris campaign probably made the wrong choice with Walz and never should have stopped mocking Republicans for being “weird.”