That's not really based on anything imo. Man United was a poison chalice and everyone could see that they needed a massive overhaul/massively overachieved with the team from the season before. Real Sociedad aren't the sort of team to be pulling up trees in La Liga and even though he didn't do well, it's not unlike them to be in those positions, and he was only given one year in a country speaking another language. You can't just write off his 11 years at Everton because of 2 seasons at other clubs.
It's a lot different managing a team for years and knowing everything about the club inside out and being in control of everything than it is coming into a new club. Moyes has failed badly in his last two stints coming into a new club and the last time he did well in that scenario was 14 years ago when football was very different