Surprised no one has NY as flippable by 2040. Upstate eventually voting like West Texas/reverse Bronx is not a crazy scenario.
Too many Democratic spots upstate -- Albany, Troy, Buffalo, Rochester, Syracuse, etc. An 80% margin is a stretch. Furthermore, Upstate NY is losing population each year while NYC continues to grow.
Right now, the GOP gets 50/50 in Upstate NY in a good year. If upstate trends far right and they start to pull 65%-70% upstate, they might get a max net gain of 1.5 million (750,000 GOP gain, 750,000 Dems loss). The GOP loses NYC by 2 million most elections. So that still leaves a deficit of about a half-million votes or so.
Basically, the GOP won't be able to contest New York State unless they also start winning the suburbs in NY. That means Long Island and Westchester. Republicans are losing these places 65-35%.
When Reagan won NY in the 1980s, he did so by:
1). Holding down the NYC deficit to 60% (instead of the ridiculous 75-80% right now)
2). Winning upstate by 2-10% points (i.e. - slightly)
3). Winning Westchester & Long Island by about 20% (i.e. - blowout). These areas gave him about 300,000 - 400,000 votes over Carter in 1980.
Westchester & Long Island are the key, not Upstate. And these areas are trending Democrat right now.