Sure Utah has won a lot recently against BYU but I don't think that's a guarantee to continue.
From 2014 to today, Utah has won 61% of their games against P5 opponents. I don't think their win % against BYU over the next decade is going to be massively better than that.
I'm also not frankly sure Utah has made some super special effort to beat BYU each year (any more than we make to beat them). Utah's just been stronger in general this past decade