I don't know. This seems like a situation where you're wrong until you're right.
If you pick five bad GMs in a row, but the sixth one wins the cup, who cares about the five losers.
There are only 31 (soon 32) of these jobs. If a candidate is afraid to take the job because he might get fired if he makes a mistake, who wants him?
At some point, the odds dictate that an owner will pick a good GM. I'd rather the owner play those odds that sit around concerned about his reputation as another season goes down the drain.