If we have 300000 supervoters left, and they are 300K plus up, isn’t that not a good thing?
It's a good thing. The GOP is cutting into the Dem lead (VBM + IPEV) by about 30K ballots cast per day. And seven heavily GOP counties just started IPEV today. Nine days left until 11/3. Potentially 9 x 30K (average deficit reduction) = 270K. Could conceivably be a virtual draw going into election day. Not a good position for Democrats. Some people are estimating a 100K overall lead for Dems going into election day. Still not a good position for Dems, given that so many are voting by mail and so afraid of the Wuhan Virus, and the GOP still has so many voters chomping at the bit to vote in person. Republicans traditionally win on election day.
Byecomey has mentioned this stat frequently, but it's worth repeating. In 2016 the Democrats led by 310K ballots cast in NC after early voting. They lost the Tarheel State by ~178K votes. That's an election day swing of nearly a half million votes in one state (presuming all Dem ballots = Dem votes).