Ok, I just think you underestimate post-injury Ronaldo. He lost some of the explosiveness but he was still a beast of a striker. A different beast you could say. While he was a freak of nature before, he was now more of a predator type of striker with great movement, goal instinct and enough pace and skill to still be way more dangerous outside of the box than Ruud ever was. He still individually was a better player than Ruud, more difficult to mark and less relied upon service around him.
Just to add, post-injury Ronaldo won World Cup with one of the best performances in that tournament, won La Liga and individually won his second Ballon d'Or and was top La Liga scorer. He still had 3 world class seasons in him which for me was better than what Ruud produced in that time. Henry is a good shout when we are talking about post-injury Ronaldo, although it's still pretty damn close. Ronaldinho and Rivaldo played different positions, although I think even Rivaldo and his family would not put him ahead of Ronaldo.
So, he had about 8-9 seasons at the highest level if you include his PSV years where he already was on the incredible level at that age and when you looking at his whole career, ability wise and because of his individual skill, you are talking about one of the best strikers in world history.
In the modern era, I would put only Marco Van Basten close to him. He certainly can't be talked about as the GOAT, injuries prevented him from being in this discussions, but when you are talking only about world best strikers or pure "number 9" in the football history, his name will always be there, at the very top.