There is a reason why top clubs are historically located in the North and not South of Italy. I`m thinking of values like organization, ambition [demanding club with demanding staff], strategy, determination, work rate and winning mentality.
Most successful clubs are based in the north of Italy, in particular, simply because of money.
Not some metaphysical reason which makes Italians from the north better people with their determination and work-rate, it's just an extension of socioeconomics.
Where there is money, there are successful clubs. You can correlate Serie A's decline with the stagnant Italian economy and in fact, we can extrapolate and state that every other country's domestic league is pretty much as powerful as its economy nowadays.
The same differences may apply to certain nations/regions, with their own exceptions from this theory. There is a reason why we usually prefer argentine players rather than brazilians, but this also has its exceptions.
About Latin American football talent imports in Europe, we have to dig into some stats to be fully objective, but my subjective view on the matter is that both countries continue to be the main exporters of talent in the world.
If you're talking about why we and Serie A in general, prefer players from Argentine, we could argue that foremost, many Argentines have Italian roots (like Messi, to name one), so they have or can easily acquire Italian passports. A very valuable asset, when it comes to foreign player quotas. I'm guessing that a certain percentage of them also speak Italian and all in all Spanish is more similar to Italian than Portuguese. That said are there more Argentine players in Portugal, than Brazilians? I doubt that, and it has nothing to do with mentality, work-ethics or what not.
Also, I'm guessing here, as I follow neither the Brazilian, nor the Argentine leagues, but I think the Primera is more related to Serie A than the Brasileirao - slightly more defensive and tactical. A testament to this could be Gabriel Barbosa's current situation, and I fail to remember an Argentine import that had such troubles settling in, especially hearing similar comments that he should adapt to the playing style.
If you have the money, it seems a safer bet to make sure our dominant contingent is italian. They may feel more attached to the club, knowing its history and perhaps willing to make history, not just coming over to play for big salary like Yaya Toure/Witsel - mercenary kind of guys. Loyalty is unfortunately a rare value in today`s football.
Well, the most loyal player in our modern history is an Argentine. Go figure. And albeit I agree to a certain extent that Italians are expected to be more attached to the badge, this doesn't change the fact that it could be the opposite. For example, our very own youth product Balo - a faithful Milanista, doesn't miss an opportunity to prove his love to our cousins and his disloyalty towards us on every occasion, although Inter has given him a place under the spotlight. And there are many more players that were rooting for city rivals in their childhood but gave their best elsewhere.
Anyway, I'm trying to say it's no guarantee and it goes both ways, but that's not what's important. Skills should be more valued than loyalty. Schelotto seemed to love the club with all his heart, after all, he tattooed his derby goal against Milan on his forearm, but this did not convert him into a club legend, not even a decent rotation option. Santon and Ranocchia have basically spent most of their careers with us, born and bread with Inter, but are they starters?
And now, to your original post.
I have a good feeling about this transfer since all the elements are there for his success, but for me the most important factor is MENTALITY . Born and raised in Bergamo [between Milano and Brescia - where Pirlo was born] - this is a crucial factor in players reaching top potential and constantly improving. This is what Brazilians usually lack, and they start to decline towards the end of their career.
I can name some names if you'd like - there are as many consistent performing imports from Brazil, even in the dawn of their careers, as there are Adrianos. The sheer volume of Brazilian players in Europe makes it easy to find patterns. What about Miranda, a player that is a pillar of our defense and is almost 33, is he a lazy and mentally weak Brazilian?
Anyhow, we should understand that it's much easier to play in your home country - you don't have to travel an ocean to see your friends and family, and everything you know from childhood. It is only human that some players get homesick, decline and move back to their country of origin for the rest of their career. Tevez could still play on top level in Europe, but he chose to go back to Argentina (and now China for a final payout, also understandable).
Italians usually age like old wine, because they keep pushing themselves and are hungry for more. You guys probably know the mentality differences between North and South of Italy, so I'm confident he will be a great player one day.
And what about good old Ranocchia, born in Assisi, north of Rome? What went wrong with him? Didn't his personal motivator help with the mentality issues he was having? Or was he simply not born just north enough?
Actually, one of the better Italian players in our squad, D'Ambrosio, was born in Naples. Some other players born in the South of Italy - Criscito who's Darmian's alternative, Quagliarella, Abate, Cannavaro, Di Natale, Donnarumma, Immobile, Conte, Gattuso and so on and so forth.
Generalisations only take us this far.