Whether or not Pogba leaves us depends solely on him. Im sure that the world was going crazy over Giggs, Scholes, Del Piero, Maldini, Totti in their youths and still they stayed their entire careers with their respective clubs. Its not the agent who makes the players leave a club, but the club and players themselves.
Look at Ibra for example. World class, but a dick character. A mercenary. I dont care who his agent is, its purely Ibra's decision to live the life of a camel mercenary.