The difference in the tight games and scores does have to do with talent, and they have a slight edge there, but not by much. The bigger advantage is coaching. They come better prepared, more motivated, and do not freeze for the most part when the game is on the line. Last year was a little different, I saw a ton of dropped balls by both Utah and BYU and a lot of nerves on both sides of the ball. Utah in 5 of 6 games has had the swagger, except last year where, there were way more mistakes. (partially due to Kalani and co IMHO, and partially due to the Ute offenses inept performance V. BYU the year before in LV).

But lets take a look at the overall talent on the 2016 rosters:

Utah: 6: 4-star athletes, 52: 3-star
BYU 6: 4-star athletes, 44: 3-star
http://247sports.com/Season/2016-Football/CollegeTeamTalentComposite

I did not do the arithmetic on all of the current players coming in, and 247 has yet to publish their 2017 composite team rankings. But my guess is that they would still have a slight advantage in overall recruiting. However, based on numbers and performance, I think the overall talent is much closer than either side thinks.