In some ways their Patreon tiers are already hiding some content, at least for a time, in the same way GB's Premium membership does. GB just does it a lot more cleanly, and it's easier to understand what you get for what price than KF. KF's Patreon model with two separate Patreon's is a bit of a mess to me, but they're getting a lot of money from it so go with god.
I much prefer GB's model though. $50 a year and you get everything, and with no ads. I do understand that GB is probably an edge case though, and running your own service is expensive. I believe I remember Jeff saying that if he was trying to start GB today he would probably turn to one of the crowdsourcing platforms.