Since his name was brought up...
Xavi did things on the football pitch that Messi and Ronaldo don't and can't do, things that took years and years of practice and highly advanced tactical notions about how to play football in a possession based progression system. Many people don't really understand how important Xavi was for Barcelona and Spain. Somebody said at some point that when you had Xavi on the pitch, decisions were made for you. You had a certainty that the ball would come at the right time, with the right power, always on your stronger foot. It would always find you moving forward, without having to stop or to turn. You would never receive under pressure because he absorbed it for you and never released the ball to get rid of it, or to put others in trouble. He used passes to create, temporize and develop the play. When you have a teammate like that everything gets easier. Xavi knew his teammates to perfection. He passed the ball to them almost like they would've passed it to themselves if they had Xavi's ability. In a game where every lost second counts, he was the no1 reason other than the system itself, for why every team on the planet parked the bus against peak Barca.
Messi and Ronaldo can never be a class above the likes of Xavi. Because they didn't have to do the type of job he did, and even if they tried, they would've failed. Ronaldo isn't even in the same league regarding passing range, ball retention skills, orchestrating play etc. Messi, on the other hand, has some of Xavi's attributes, while completely lacking others, like the ability to run 11-12km. per game and have such a great movement that, at any a given time, almost every teammate could have passed the ball to him. Again, imagine you have a teammate that you can always find when you are in trouble, a player who you know will control even the most difficult passes and complete a better pass in 1-2 touches. A lot of times it was almost like a 'get out of jail free' card, that would allow you to keep the ball, instead of losing it. Imagine that kind of influence on the game.
How can someone say Ronaldo is leagues above the likes of Xavi beats me.
This whole talk about who the greatest is is all rubbish anyway, even if everybody indulges in these 'debates'. There is no one I've seen who can do what Xavi did better than him, and that tells you right there that these things are purely circumstantial. Among all-time greats, there is no one who has all the abilities, because no one has to in the first place.