They quite apparently thought a substantial gain in social media following was worth abandoning an even, well-constructed quality team.
Don't you know the young people don't follow football games anymore, just watch clips on their mobile phones? If Agnelli and Perez are to believed?
I don't have an issue with the social media side of things, it's important for the long term development of a club like Juventus who has the potential to be far closer to the top from a commercial standpoint but Ronaldo isn't the player for that because you need to target younger people, people that will follow the club for the next decade, Ronaldo is the hero of an "older" generation and will be associated with Real Madrid until the end of time. It makes even less sense when Ronaldo didn't fit with their on field project, he is great and has been prolific but his contribution is hollow because it didn't make the team perform at a higher level.
And where are they now, they will never get their money back, they didn't elevate their profile and haven't been more successful. They also played some of the worst football in Europe since 2018.