Biggest issue here for Biden is this:
Biden 2020 voters: 80% Biden, 3% Trump, 17% neither/other
Trump 2020 voters: 88% Trump, 5% Biden, 6% neither/other
The thing is, the question is if its real because polls have been all over the place in terms of who is consolidating the most voters. But if it is real, it again points to the truth that Biden voters are not flipping to Trump (ironically, more are flipping the other way around here), but that Biden needs to get the more ambivalent folks who don't want Trump but don't love voting for Biden again either.
Though, Biden only getting 76% of Ds and Casey only getting 80% also presents that this isn't really a Biden specific issue either. I think a lot of these PA polls are just getting kind of messy Democrat samples.
The lack of enthusiasm for Biden is certainly a concern but I do believe most people will hold their nose and vote for him just because they don't want Trump. Turnout will be a problem but the x factor might be increased turnout by young women due to the abortion issue. Without the abortion issue I would have said Trump has the advantage but the advantage flips to Biden due to this issue.