> It's only these handful of swing states (WI, MI, PA, NV, GA) that have such a massively different ratio of votes in-person vs. mail-in.
No, its not.
Its only those states that got a lot of attention to their count because they were swing states; the states that were easy to project very early on, no one outside of the media decision desks making the call cared about the details. And lots of them didn't have rules separating and delaying the count of mail-in ballots, anyway, which meant that differences in mail-in ballot patterns (which there almost certainly were because of partisan differences in who voted mail-in, entirely predictable given partisan differences in advocacy for and against mail voting) wouldn't show up clearly in the count timing the way it does in places where the process delayed starting counting mail-in ballots.
