Marotta can be whatever he wants to be, people believe in him because he had a track record of making whatever he did worked. He has been 'lucky' for decades, maybe it's time for you to consider luck a serious skill.
Well, he was lucky that Zamparini made him what he was when Venezia was rising from Serie B, he jumped ship when things turned to shit and then moved to a team in disarray that soon after ended up being taken over by an ambitious owner at Sampdoria.
Juventus came knocking after a good Sampdoria run, he had a very bad first year dismantling half the squad and then with the new stadium, heavy investments, refereeing help and abysmal performance by Inter, they won the league in 2012, which was their announced target btw, something that people like to leave out.
So yeah, I think lucky qualifies here. If you think he had the foresight to see that Sampdoria would have been taken over and call that skill, I don't know.
He's very good at his job, no one denies that. And he's experienced at all possible levels, but his management style will probably annoy us more than it will makes us happy in the near future.
Are you ready to sacrifice De Vrij, Barella, Lautaro and Skriniar for the sake of Marotta's pawn moves along with some misfires like Brozovic? If so, you're well equipped for what's coming and I envy you.