I'm going to try to keep this brief, but in this thread I want to suggest that a key factor to Oklahoma State's disappointing nationals performance was the fact that they came into the competition in a vaccum. That is, they had no real context for judging their abilities relative to the rest of the field, and had yet to toe the line as a team in an all-out effort. This, combined with their high expectations, created a disaster waiting to happen. What follows is my reasoning; if you want to skip it feel free.
Without Fernandez's injury, Oklahoma State would have been a distant third. There's really no argument about that--no matter how you slice it, it was a bad day for them. But if you look back at their season, you have to wonder if it was reasonable to expect them to finish any higher. If you look at their three biggest races prior to nationals--pre-nats, conference, and regionals--you see that they really had no context for their own fitness. Pre-nats was the perfect opportunity to give the team a competetive measure of its ability, and instead a trend of controlled, time-trial style racing emerged. Their times indicated a strong finish, but they didn't actually compete against anyone. Coach Smith's decision to run his top guys in the Pre-nats open race may have been an effort to avoid showing his cards, but it actually left his team in the dark. Fast-forward to conference and perhaps the most misleading race of the season where the Cowboys go 1-3-4-5. Fernandez's defeat of Songok here was encouraging, but in hindisght Songok himself was operating in something of a vacuum. He would go on to win the weakest regional against an opponent who was also probably overrated (Kosgei of Lamar), and finish a disappointing 22nd at nationals. And although Iowa State had some frontrunners, the Cowboys essentially dispatched a bunch of guys who, on a national level, were middle-of-the-packers.
And regionals provided no further information. The Cowboys again avoided a green-light, from-the-gun effort, and as a result the entire race unfolded in a very un-nationals way. Something like 40 guys shared the lead at 5k in the 15:40s. There were some top-20 caliber individuals in the field in Mead, Rombough and Beattie, but Oklahoma State didn't actually beat those guys in the race, with the exception of Kosgei besting Beattie. The assumption that because it was a controlled effort the Cowyboys could finish ahead of such guys at nationals was of course only an assumption.
Ultimately I think this vacuum was a problem for Oklahoma State. Obviously a team has its own information based on workouts, performances relative to other years, etc. However, this year's Oklahoma State team was isolated from competition in a way that we do not often see. Add to this a fact that Coach Smith was being quite explicit about their mindset going into nationals--they expected to win. The Brojos praised him for his candor, but in hindsight he may have done better to downplay their chances. Clearly what a coach says in interviews and what he says to his team are two different things, but his words are indicative of a team that may have overestimated its own abilities.
So, as a result of their competetive isolation and their candid expectations, the Cowboys showed up to the line Monday without an accurate perspective on where they stood against their opponents and with a significantly overestimated assessment of their chances. The result was severe disappointment.