Ronaldinho was mostly party lifestyle and he kind of lost his motivation after he won everything important and somewhat recovered some of it when he back to Brazil
Ronaldo was mostly injuries and hypothyroidism which he didn't take illegal substances to treat the latter btw so every time he went from fat to skinny he did it the hard way. He didn't party as much as Dinho, he said one time he had more nights with Roberto Carlos than going out partying with girls
Ronaldo for me never felt like he lost his motivation and never felt like he wasn't having fun, that is a huge difference.
Neither of them took training seriously(in one video Mourinho says that he saw Ronaldo at Barcelona and he was just having fun in training like playing at the beach... it's very weird to see Mourinho emotional like that btw) but Ronaldinho seemed to sometimes not enjoy playing football at all while Ronaldo always seemed to be having fun and always seemed to have his head in the game even when he had off-matches. That's part of the reason why to me Ronaldo is synonymous with Football.
Ibra says it best ''Ronaldo is football''. I remember a few years back I watched Ronaldo play one of those retirement matches, and even though he was fat and barely walking the moment he touched the ball I felt like almost bawling. Watching Ronaldo play reminds me of the joy I had playing football as a kid. There is something so pure, uncynical and precious that goes even beyond his skills and achievements.
