for saying so.
I think they earned much of that acclaim - especially before joining Pac12 (Undefeated season, Sugar Bowl, etc). They continued to have great defense and KW is a really shrewd and tough coach. And there are a lot of long-time Utah fans who were just along for the ride and thrilled to have that success. And there were some big wins (eg over pretty good Oregon teams)
But you are so right about the overall phenomenon - so much anti-BYU animus, it warped them. And they believed their own hype and then some. Got a lot of lucky breaks and saw it as proof of superiority. Craziest thing is to see it fall so fast.
Character is fate.