When Jimmy Carter pulled the rug from under the Shah, he begin the chain of events that are still going on today.
The hostages were fortunate that none of them were murdered.
In my cynical opinion, that might have been the plan. I don't see any chance that the "rescue" in the spring of 1980 could have ever succeeded, but OTOH there was an excellent chance it would result in all the hostages being killed . . . and the end of the day-by-day countdowns on the evening news, well before the November election.