You’re going to see more registered Republicans crossing over to vote for Harris than perhaps any Democrat has previously received.
I'm fully aware thats the assumption people are making. Its not clear how good or bad of an assumption that is. Its also not clear what damage Harris has done with Democrats relationship to the Arab/ Muslim/ Anti-genocide Democrats. Two weeks ago this thing was in the bag for Trump to the point he was just dancing on stage cus he knew he didn't need to do anything else to win. Then he had a Nazi rally.
Pretending like this thing is in anyway a shoe-in for Harris seems to be oblivious to the facts on the ground. She campaigned extremely poorly and made bad strategic choices that took her from heading towards a blue-wave the likes of which we've never seen to now, a blue whimper. Look at how Harris is doing relative to down-ballot Democrats (538) (D's left, R's right, senate where possible, house where not):
Pennsylvania:
Harris 47.6, Trump, 47.9: -0.3 to team D.
Casey 49, McCormick 46: +3.0 to team D.
Harris delta: -3.3
Michigan:
Harris 47.9, Trump 47.1: +0.8 to team D.
Slotkin 49, Rogers 47: +2.0 to team D.
Harris delta: -1.2
Georgia:
Harris 47, Trump 48.5: -1.5 to team D.
Bishop 47, West 44: +3 to team D.
Harris delta: -4.5
Arizona:
Harris 46.5, Trump 49: -2.5 to team D.
Kelly 48.6, Masters 47.1: +1.5 to team D.
Harris delta: -3
North Carolina:
Harris 47, Trump 48.5: -1.5 to team D.
Beasley 45.2, Budd 49.5: -4.3 to team D.
Harris delta: 3.2
Nevada:
Harris 47.1, Trump 47.9: -.9 to team D.
Cortez Masto 45.9, Kaxakt 47.3: -1.4 to team D.
Harris delta: 0.5
Wisconsin:
Harris, 48.1, Trump 47.4: +0.6 to team D.
Baldwin 49, Hovde 48: +1 to team D.
Harris delta: -.4
Averages out to about ~ -1.25
So in general, Harris is under performing "the average Democrat" in the swing states by about 1.25 points. Keep in mind, Harris was leading or damn near leading at one point in most of those races, and was on track for more substantial gains going into the convention.
She may win in-spite of those major mis-steps, but its not a forgone conclusion that she will win either. Also, it still has to get through all the states, the supreme court if that comes up, and then finally through the certification.