Menez with an even worse Milan side managed 16 creating his own chances and goals in a false - 9 role and even Menez had his faults with being selfish.
The entire idea is what works best for the team. Bacca does not work for Montellas game and you're going to ask me why. First of all Bacca is a short manlet that can't catch his breath and won't be able to pressure defenders like Niang. Second of all Bacca offers no fantasy/ruthlessness to the attack. Poaching in soccer is one of the easiest thing you can do. Even I can wait for my team mates to do all the work receive the ball and tap it into the net, that's actually my favourite cause it means I don't have to run much. Players like Mandzukic, Griezzman etc are a nightmare for defenders because they offer pace/skill/physicality that makes it hard for defenders to deal with. Chellini can murder Bacca and grill him in his BBQ. The reason why Montella wanted Gomez at Fiorentina was because Gomez can do the same thing as Ibra/Mandzukic/Pazzini where they can receive the ball and hold it against a defender which allows the attack (wingers) to rush forward, receive the pass and create something. If you have a Pizzaro/Montolivo/Bonucci play a super long ball from a counter attack, you'd have Mandzukic/Pazzini/Gomez chest that ball and hold it until someone like Cuadrado comes in to receive a past to go in behind the defender. Allegri's Milan did this all the time with Ibrahimovic. That's of course one example. And of course all 3 of those players were foxes in the box and were able to score at any time via their head/feet/whatever when they receive a pass which is what we all applaud Bacca for being very good at.
Bacca may be amazingly good at 1 thing, but he sucks at everything else and players like him are a dying breed. At Barcelona Bacca would never fly because he does not offer the kilometres Neymar and Suarez offer or the talent Messi has. Even at Real Madrid Benzema is always pressuring players and providing passes to Ronaldo. So stop giving me that shit about "bro he needs a midfield". These are all players with world class midfields who still offer 1000x more than Bacca which is why they are where they are. The game has changed. Why did Pelle work so well for Italia? Kilometres, physicality, and height. Pelle was amazing at holding the ball up and he could finish chances. 2 is always better than one