It's more to do with Ronaldo being the stand out player at every club he has been at. International and domestic. Literally carried Portugal to winning the Euros. Made Man utd, Real Madrid and Juventus better and still stood out.
With Messi, obviously unbelievable player. But Barca have then built the team around him and to suit him. They haven't been as good in recent years and Argentina have been nowhere near as good as they should be. I'd say they've had a better squad than Portugal for years but it never shows and Messi doesn't seem to have that influence that Ronaldo does.
So I've always been waiting for Messi to go to that other club just to see if he can sustain they levels at a club that's not been built around him and then I'd step back and just applaud them both equally.
Just my opinion right enough