The difference between haves and have nots was not as big then as it is now. BYU was near the top of the have nots then and Utah did not have a seat at the haves table.
The biggest thing BYU could do for its winning percentage is to schedule more congruent with what it has. I like playing the better teams myself but I am resigned to 6 win seasons as acceptable. Many don't seem yet resigned to where I am at.