There's two different things:

1- keeping information behind a paywall.
2- keeping the verification to some people 

OnlyFans success shows us that #1 works <well enough> for people to spend some sats to climb those paywalls.
We know that information could be broadcasted to the world, but still nowadays OnlyFans is a thing.

nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z 's proposal allows to implement #1 well enough, and even adding #2 to it.