I see you were not a member of Simbella, then.  Simbella was notorious for that. And they had exclusive content that you could have if you asked and did not share with anyone outside the forum. But of course they also had super exclusive stuff that the inner circle shared among themselves.

Also, take Aikea_Guinea. People are obsessed with her sims because they cannot have them. Also, she has some things she refuses to share with anyone, thus everyone tries to kiss her ass as best they can, because if you become one of her chosen ones, she shares her stuff with you.

To a certain degree, all paysite stuff is all about exclusivity. Not all can afford it, thus if you have it, your game is better than others.