Sony is

ing smart. The transition is basically complete.
1. Rope people in with a deal too good to be true in 2012 with the IGC. Get them used to paying $50/year for a subscription.
2. At PS4 launch, require subscription for online play.
3. Slowly dial back the "quality" of free games to save money.
4. Nobody who owns a PS4 is going to leave Plus unless they're willing to abandon online gameplay.
Don't get me wrong, quality is super subjective and I love indie games and I'd prefer more indies than retail releases in my Plus lineup. Velocity 2X, Dust, and Binding of Isaac alone almost justify the $30/year I paid. But no doubt games like Escape Plan/Hungry Horde/Frozen Synapse Prime don't cost nearly as much as Dragon's Crown/Arkham City/Bioshock Infinite.