You're not wrong, but I think you've missed my point a bit. I'm not saying he needs full control, this isn't the 90s anymore. But he's got close to none. He has seemingly no say on transfers. He has no say on where they play preseason. He has no say on who's contract gets extended. He has a block on him with what he can say at times.
Chelsea, Inter, and Real Madrid all gave him some control. They all adapted to him and were supportive. That was the undoing in the end but it always brought some success initially. He's shackled at United because they have an MO based on public perception and they're trying to limit Mourinho's ability to damage it.