There's no guarantee it works for Moyes at Everton.
He's had torrid periods at West Ham, Man United and Everton where he couldn't get results and fans wanted him gone.
Parachuting into a troubled club, which has circled the gurgler for years, at a critical period, where mistakes could be VERY costly, isn't nailed on to work out.
We got really lucky with Saint Nigel, but they they say "never go back" for a reason.