Failure has no correlation to success, only the (in)ability to learn from failure.
Table one year ago:
1. Ferguson (retired)
2. Mancini (sacked)
3. Benitez (contract expired)
4. Wenger
5. Villas Boas (sacked)
6. Moyes (sacked)
7. Rodgers
...
18. Martinez
Table today:
1. Rodgers
2. Mourinho (sacked at RM)
3. Pellegrini
4. Wenger
5. Martinez (relegated)
6. Sherwood (to be sacked)
7. Giggs (interim)
Let's be clear--I'm not predicting some huge success for Moyes in the future, but I think your comment is a bit overreaching/overreactive.
My point was he will never be picked to permanently manage one of the biggest clubs in the world again. I stand by that assertion.
He failed on the largest stage with his first 'big' club. Mourinho is bullet proof. Mancini won a league title. Giggs is interim, Sherwood is never going to end up managing one of the big clubs. It doesn't matter whether he could be successful, it matters that no global club will give him the chance unless they fall mightily.
Can you imagine Bayern, Real, Chelsea, or Barca going in for Moyes? Ever?
Also, I was making a lighthearted joke about how Everton will be top of the league shortly, and we would never bring back a manager 'proven' to be incapable at that level. That in 5-10 years someone will say: Could you imagine Bayern, Real, Chelsea, Everton, or Barca going in for X? Ever?