Or yes. Tell us how UA could have foreseen that aircraft N14153 flying on time from Grand Junction to Denver, having had all its earlier flights on time, scheduled to fly from Denver to Louisville and its crew scheduled to fly the next morning out of Louisville, would get stuck in Denver precisely at the moment the other plane from Chicago to Louisville was boarding or already boarded, and while other flights were departing Denver on time or with small delays.
How would have UA predicted that an aircraft that had been flying in perfectly working condition would not be able to get out of Denver on time when there were no weather conditions disrupting operations massively?
Again, there are multiple issues. One is that either United or Republic were somehow unable to realize that they were up a creek with the situation until the flight had already boarded [1]. That's a real problem and arguably the crux of the issue.
Another is the lack of "protect" crews and equipment: Schedules and equipment utilization have been rationalized to the point of irrationality. That United or Republic was in this position to begin with, where this whole cascade could qualify as a crisis, is the result of bad incentives and bad policy.
[1] United's assertions to the contrary, I believe the past tense is appropriate here.