I spoke to my friend who runs a PAC (along with 6 others I learned tonight). His PAC does GOTV nationally and they had money left over. Learned some stuff that was news to me. Sorry if some or all is common knowledge here.
Prior to June debate, internal polling had Biden with a small but consistent lead over Trump. The day after the debate, his PAC, including him, met with Biden campaign, and the campaign was insisting that everything was fine. The key data that convinced Biden to drop out was internal polling showing he was a huge drag on House races. Biden purposely waited to drop out to make sure Harris would be nominee. GOTV operation was underfunded in battlegrounds. He said only 1m was allocated to all GOTV in Philadelphia. He thinks Harris campaign spent too much on broadcast ads not enough on targeted ads and GOTV (not surprised by his bias re: GOTV). The counties he was personally responsible for in FL Harris mostly won or did better than expected.
The difference between internal and public polling is huge according to him. Internal polling has voter lists that they use to target calls. Internals are in the field longer and more persistent with call backs. They ask better, more targeted questions. They have a much larger sample size.
He was very disappointed, not a surprise. I was surprised by how much he wanted to talk.