I will give you other Ronaldo as other example. I am from old era, so I better know this Ronaldo.
Old Era Ronaldo wasn't so fit towards the end of his career at Real Madrid, for example. I remember he would get criticised at Real Madrid for being overweight and had poor form at times. That was between 2005 and 2007 if I recall well.
Even if you have a very good skill, if you don't have good body physique and not fit enough, it will affect the way you play especially at top level and end up warming the bench. Look at what happened to Hazard.
Hazard was not always the most professional guy in his career but he also just got a lot of injuries, which is one of the reasons he retired. People are saying that Luis Suarez is old and while that is true and he will not be as good as he once was, the soccer competition in US is still on a lower level than compared to Europe, so he can still make a (huge) impact.