Mourinho doesn't build teams though; he buys them. Moyes has shown an excellent record in helping youngsters develop, and also buying players cheap and letting them grow into much better players.
Even if that was wholly true, which is not, he's still remarkably successful. We have plenty of examples that shows us that splashing money around doesn't mean you'll win trophies, at least not as fast as you will with him at the helm.
Since he left Porto, he's had amazing squads, no doubt. But he earned that privilege through his competence and consistency. And he never disappoints. Not at Benfica, Leiria, Porto, and everything else beyond. Perhaps Real will be his most underwhelming club. He may very well leave after 3 seasons with "only" a league title and a Copa del Rey. But even that is marginally impressive when we look at Barcelona.
He rarely if ever disappoints. Does anyone remember him being dicked around by any other team apart from the odd Barcelona game? Very rarely that happens. He may not win the Champions League every year, but not once he was thrown out of it in an embarrassing way.
Certainly the best manager in the modern era of football. I'd say that discounting Sir Alex Fergusson whose career was so particularly different than every other manager that makes it impossible to draw comparisons. What he built with you lot is something extraordinary and he's had a much wider role than Mourinho will ever have at any club.