Dom Luszczyzsyn also predicted the Sabres would be dead last last year...the Canadiens would be 19th...the Kraken would be 10th...and the Golden Knights would be the 4th best team in the NHL. How'd those work out?
https://theathletic.com/2843332/2021/10/08/dom-luszczyszyns-2021-22-nhl-team-previews/
Like I said earlier, Vegas knows what bettors think, not what teams will do. If enough people think like you and bet the under, the line stays at 77.5.
So they are reducing the payout for the over because too much money is going there.