No matter how good a team is, they can’t outplay the spread all season.
The Kansas City Chiefs had the best record in the NFL and went 7-9 against the spread. The Los Angeles Lakers were the runaway favorite to win the NBA championship and they’re just 4-3 against the spread.
The reason is obvious. Once a team is playing well and bettors notice, sportsbooks adjust. After a while, oddsmakers can’t make spreads high enough; casual bettors will always back teams like the Chiefs and Lakers no matter the line. The spreads get so inflated that elite teams can win but not come close to covering the spread.