I feel like we're on different pages here
I'm agreeing with you that most celebrities that have liked sneakers for a long time are probably familiar with NT. However, I don't think most of them bother becoming members because there's no reason to.
Dom, Wale, and Stalley are were all NT before they were getting rap money. I could see Trinidad James being a member before his career took off. Wiz signed up just before things fully took off I believe, and that was more than likely through a friend. Curren$y is probably just a lurker.
I could see Kid Cudi, Big Sean, and Drake lurking in a past life too. As for everyone else, I could see them learning about it from a friend, glancing at it once or twice, and never really coming back; especially with sneaker blogs being larger than ever. They don't need to lurk here and scroll past tons of nonsense to get some info any more.
I'm saying, that just like how you said Bow Wow more than likely knows of this site just from being into sneakers for over a decade, I feel like most other famous sneaker lovers are the same.