I believe whoever first brought up Ronaldo returning to Man United here, he must have made it up. I didn't even find which media spread the rumor about Man United and Ronaldo. Logically I agree with you because it is very unlikely that Man United can give a bigger salary to a player who is already old even though he is a star player, but surely Man United management will consider not bringing the player back to the team.
I was surprised when I saw the discussion of Cristiano Ronaldo returning to Manchester United for the third time this season. I searched online if I could even see a rumor that linked Manchester United and Cristiano Ronaldo, and I didn't even see any rumor, so I agree that the person that brought up Cristiano Ronaldo returning to Manchester United just cooked up the story.