Realistically speaking, Utah has been the stronger team/program over the last 18 years since Urban Meyer showed up. But even admitting that, there's no way the streak should be older than the deacons passing the sacrament. That's just a streak of bad luck, and statistically improbable.

As long as BYU is a decent team, the game should be close and that means there is a chance - streak has to break at some point and the talent gap frankly isn't as large as other "rivalries" that have shorter streaks

South Carolina last beat Clemson in 2013 (capping 5 years in a row)
Georgia Tech beat Georgia in 2016 and 2014
Colorado State beat Colorado in 2012 and 2014 (particularly notable since this is one of the only other P5/non-P5 rivalries out there)
Oklahoma State beat Oklahoma in 2011 and 2013
Oregon State beat Oregon in 2016 and 2020
Texas Tech knocked off Texas in 2015 and 2017
Even Utah State beat Utah in 2012 (they've only played twice since so probably not a real rivalry since Utah went P5)
Speaking of Utah State, they've beaten BYU in 3 of the last 6 meetings
Auburn has beat Alabama 4 times since BYU beat Utah

The point is that even less talented teams do beat their rivals sometimes

Minnesota lost to Wisconsin for 14 years before getting a win in 2018
Virginia lost to Virginia Tech every year from 2004-2018 (15 years) before getting a win in 2019

Simply put, BYU's due to get the right result one of these years relatively soon. And no reason it can't be this year. BYU's not transcendent, but neither is Utah. And neither team looks historically weak either. So Utah is likely favored, but if BYU has a 30% chance, that's a real chance.