Rangnick had six months in charge of United during the 2021/22 season.
He told Sport: "Since I left, they have spent £700, £800 million and the team is 15th. They have changed coaches many times.
"Now there is still (Ruben) Amorim, who is a very good coach, but if in the end it doesn't work out, another coach will come, with his new system of play or philosophy, he will bring other players...
"And this brings us back to what we were saying at the beginning about Johan Cruyff. There has to be someone who decides what the planning is."
Rangnick also said: "I think we have to go back to 2013, when Sir Alex left the club. And when he was still there, he was the mastermind of everything. He probably also brought a lot of important people to the club.
"And when he left, some of those people probably left the club with him. Since then, I think the club has a leadership problem: who really makes the decisions and why do they make them?"
Who makes the decisions?
The German also said: "Are they really the best people for that role? I can only say that, in the six months I was there, it was difficult to understand, even for me as a head coach, who was making the decisions.
"Who could I talk to? If we wanted to buy new players, it was difficult. There were people, but in the end it was all complicated."