What utter garbage.
Shearer would have lasted 5 seasons max at Man U before Fergie booted his btackside out of the door as soon as his form slipped.
Doubt it, Shearer would have been a 10 years man at Man Utd easily, because he'd still have banged them in for fun like he did for us but just as key because he was a leader, a team-player, a strong personality. Fergie likes such characters, i.e. your Scholes', Giggs', stalwarts, real pros. Players who despite their declining form and years, he still keeps around.
The likes of Giggs and Scholes were never as reliant on their physicality as Shearer. He'd have not lasted as long at MUFC as he did here. He'd have been on the bench at best, something a personality like him never would've accepted.