For all the talk about how CR is a "drag" on Juventus finances, their revenues did increase by a decent margin when he signed.
That said, it wasn't enough to truly bring Juventus up there with the elites.
As for PSG, with FFP pretty much dead, how much Messi improves their revenues isn't that important, though i guess they value popularity all the same.
Juve paid 100M for CR (PSG paid 0
for Messi)
Without having play a single match, only because CR signed for Juve, the club raised the price of season tickets and tickets = 14 million more than the previous season, Adidas has more than doubled its sponsorship (from 23 to 51 million per year) while all those who want their name to appear behind the figure of Ronaldo signed new contracts leading to an increase from 28 to 44 million in a single season.
And for sure this is only a part of what he brings to juve.
Obviously he is not enough to take Juventus up there with the elites (as he's not enough to win the CL).
He was a step in this direction, he gave also more visibility (brought millions and millions of fans, followers Facebook, instagram,...)
And I agree about Messi, PSG did not bought Messi for the revenues, PSG with Messi changes status, takes the club to another level of popularity/visibility (without paying anything, for sure Messi generates enough money that he is not a cost to PSG). they value popularity all the same.