All that is sort of true, but keep in mind UF has had a recent AD change. That adds to the probability of a HC being replaced.
But....if a HC wants loyalty, he needs to win. 2/3 of your conference games isn't good enough at Florida, period. 2/3 of your games is usually good for 3rd in the division - McElwain lucked out and it was good enough for a couple of 1st-place finishes in the division.
UF does run the risk of scaring some prospective HCs away, but it's worth it - you can only be an elite program if you expect to be an elite program.