I think USU would have risen to the occasion with increased money and exposure. They seem to be doing very well right now with the limited resources that they have.
There is already some rivalry/comraderie between Utah and USU. The rivalry with USU and Utah was, until the 80's much, much bigger than the Utah/BYU or BYU/USU rivalries. It is something that would be easily taken to next level and be legit, unlike anything that could happen with CU.
Yes, Logan is small, but so are Pullman and Corvallis.
Pie in the sky, I know. Everything was driven by markets and TVs. Logan would have added nothing other than an additional school to get to a conference championship game.
It never would have happened, but that's my dream scenario.