Interesting question. I'd say that a game that goes F2P should exclude their lifetime members from whatever revenue model they have. If they're supported by advertisement, don't show ads to the lifetime members. If they're supported by selling premium content, let lifetime members have access to it all.
It seems like, in that case, lifetime membership could actually make for a decent ongoing revenue model. Want everything in the game, or want to go ad-free forever? Buy a lifetime membership for only $BIGNUM! Price it right and you could still make more money from those people than you'd make from having them buy bits and pieces over time. If you're F2P, presumably you've already structured the service to be very cheap to provide.
It seems like, in that case, lifetime membership could actually make for a decent ongoing revenue model. Want everything in the game, or want to go ad-free forever? Buy a lifetime membership for only $BIGNUM! Price it right and you could still make more money from those people than you'd make from having them buy bits and pieces over time. If you're F2P, presumably you've already structured the service to be very cheap to provide.