First off, those four teams were not "inferior". They had a combined record of 38-16. Nevada was the only one that I would say was truly worse than us in 2014, and they still finished 7-6 that year.
Then there's that tiny little but ever so important detail of BYU losing its Heisman contender QB to injury at the start of that losing streak and being forced to re-tool its offense to accommodate a green QB making his first starts.