A genius who is made out of glass like Van Persie, needs to be handled with cotton wool in the final stages of their career.
Moyes came in thinking that running his players into the ground, while switching the mentality from all out attack to a more cautious approach, was the way forward.
If you look at how Fergie handled Giggs in the final years, the same would have been done with Van Persie. Had Sam Allardyce replaced Fergie in that period, and got tough with Giggs, demanding that he forget about making goals and assists, and instead focus on tracking the Fulhams/Huddersfields No. 10 all game, then it wouldn't have ended well either.