Van Persie will be working in England this season as a pundit.
“It's a great place to be. But when it goes wrong, when you're having a bad period as a player or a coach, it's tough.
“It's a tough place, lots of pressure, fans demanding not only a win, but attacking football.
“They are right. We are talking about top-level players here. And they are not always producing the type of football that the fans want and need."
Van Persie added: “Top teams want to win the Premier League.
“But United have had a couple of changes in coaches. If the coach comes in you need time and some coaches didn't get time.
“Moyes got 11 months, Louis van Gaal got less than two years. Mourinho got two and a bit.
“It is sometimes better to stick with a coach and give him time.
“It is a big process, when you have 25 top players and everyone wants to play. It is very difficult to get that right. To win the league in England is so difficult."