All our best signings have pretty much been a pure strike of luck. Not even the most optimistic person in the world would think Pirlo would have such an impact. We brought him because 1. He was a freebie and 2. Italian and that's Marotta's preferred combination.
Don't even mention Pogba, there was no way we knew he was gonna turn out as he did, he barely had any playing time at United, again pure luck. Barzagli, pretty much a reject. We don't take risks. Instead there goes money out the window on players WE know won't be good enough, not even potentially. Tevez was another reject and luckily for us has found a new home in Italy. Vidal was a good player who turned into a beast, an excellent signing but not a risky one.
Morata is the only exception in recent times that we've taken a risk and we're still waiting to see if it pays off. If it does, that's the kind of approach we should've been using.