Circumstances dictate, each club is different due to its identity - take Chelsea for example they HAVE to appoint a big name, whereas Barcelona have gone down a route (until the end of this season) of appointing an inhouse manage, Pep Tito & Luis - they all won something and had a successful spell as manager - it's no coincidence that Real Madrid have now chosen to go down the same path with Zidane & guess what, it's working.
Oh yes, Zidane.
So it turns out what really matters is choosing the right man, rather than just appointing Ancelotti because you can't think of anyone else and he has an impressive CV.