In 2024 the registered voter only got such a ballot if they requested it.
I don't think that is true and guess what leads me to believe that?.....
A link you gave me 2 days ago...
https://election.lab.ufl.edu/early-vote/2024-early-voting/
But I think that link may be pointing at the source of the extra votes.
It shows that for PA in 2024, there were 48M mail in ballots requested and 24M returned.
In 2020 there were 56M mail in ballots REQUESTED and 37M returned. (they didn't mail them to every registered voter)
Those extra 13M returned mail in ballots are probably the difference but the question remains....
Did they simply forget to cheat this time?
You are correct that PA was one of the few states that sent out ballots to everyone.
I give credit to the Trump campaign for doing a brilliant job of running up the numbers in PA and keeping a close watch on the details in that state.