The goal is to set a line to get people to bet money, not predict the outcome of a game. If it worked the way you claim, Vegas loses money 100% of the time. The line opened -2.5 for Utah. The money came in on the Utes side so the bookies moved the line to -3 to get more people to bet on Oregon. If Oregon had 80% of the money and the line moved to favor Utah, more people would continue to bet on Oregon because it becomes more likely for them to cover. Then if Oregon, covers with 80%+ of the money on them, Vegas loses money. The only way for them to guarantee a profit is for people to put money on both sides.
These lines aren’t to predict a winner. In fact Utah could win and not cover. The goal in these bets has never been to predict an outcome, only to make money, which they do hand over fist.