I know at least in my country release dates for movies have come much closer to there American release dates over this period. I only mention this because one of the reasons someone is likely to watch a telesync rather than waiting for a better copy is because they don't want to wait to watch it. This lends some more credence to the piracy is a service problem argument. Though of course you could argue that downloading 4gb to 16gb files is more reasonable now days so the change comes from there.

Why do we care whether the screener was leaked "by nomination day"? That choice seems arbitrary.

Hey, I did the analysis. The nominations came out two days ago, so that's just shorthand for "at press time." I don't actually track that metric in the spreadsheet... I keep the data updated until the Oscar ceremony on February 26.