The thing is that there are countless examples around at present and throughout football history of the old adage that a good manager at lower levels would not necessarily be a good manager at the top, and vice versa. Would the likes of a Pep Guardiola be able to romp to a league title in MLS, or Denmark, or South Africa? Almost certainly not, because his system revolves around having players intelligent enough to play his system almost flawlessly, and he has virtually no capacity for altering his set-up to cope with a player or players failing to do their part. To take a non-footballing example, a legendary stock car driver would probably be hopelessly out of their league if asked to compete in NASCAR or Formula One.
True pragmatist managers like Mourinho might be capable of challenging at any level, because they base their systems around identifying their teams' strengths and weaknesses and then playing a game which throttles the opposition by utilising their players in a very specific way to neutralise the opposition rather than necessarily to play up to full capacity, but that type of manager is rare. Most ultimately will have a system or style they think works best and will look to mould their players in that style.
That's ultimately why managers who fail at one level often get chances again at a higher step - because the people doing the recruiting recognise that the manager aspires to something similar to what they want to see and they convince themselves that their players or their resources to sign players will then grant that player the ability to produce winning football where they couldn't achieve it before. The exact same will come into play with any big European team who eyes PV up. He might be capable of it, he might not. Who is to tell unless someone gives him that chance?