Utah signs a ton of 3-star guys. It then takes years to turn those guys into NFL-caliber talent. That's one of the biggest differences between 3- and 4/5 star talent. The 4/5 star guys are ready to contribute right away. They already have the build/speed/maturity/experience to step on the field from day 1. They don't have to develop as much as the 3-star guy, who has to transform his body.
Whit doesn't get 3-4 years of high-end talent. It usually takes 2-3 years for these guys to sniff the field and develop and they usually don't realize their talent until the very end of their college career. Guys like Jaylon Johnson (who was a stud from the start) are not the norm at Utah.
Utah was very lucky that a bunch of guys (Moss, Fotu, Anae) decided to stay for their senior year. That's been the biggest difference this year. Utah had pro guys on the roster from day 1.