Agreed, but he has played his card poorly since he left Real Madrid. And then he chose to leave Juve for a shit United, and now he's crying about them being shit and wants out.
Everyone with a well functioning brain could've seen it would be a bad choice going back there. But when he wanted out of Juve no other big club wanted him, hence he chose United. Apparantly City was a possibility, but it was always half hearted from their side.
Another problem is, when you play with a soon to be 38 year old Ronaldo it's like being a man down when the opponents have the ball. There's no defensive work or tracking back, everything has to go through him. When you try to build a team that just doesn't work anymore with his age. If he was in his prime it would be different, but thats at leats a handful years ago.