Who knows how SD's with more money, more press and more power that Juventus brings would be? You can't really say that you want this guy or that guy because they're doing a great job for a smaller team because he won't be in a small team and the rules change while working for Juventus. There is a difference between bringing in and having the time to nurture talents with for example Palermo than Juventus. In smaller teams a good SD is one who can bring in young and cheap players and sell them for a huge profit but in Juventus you need to bring in players that make a difference right away.
But I have no idea on what grounds Marotta got the job. His team in Sampdoria had like 5 foreigners, maybe thats a reason they wanted him? More of an Italian identity.