Will classic MMOs survive without free-to-play?

It's amazing to me how quickly the industry has shifted to where we don't just welcome free-to-play as a business model in MMOs -- we downright expect it. Take a look in the comments of any new MMO that dares to launch with a subscription-only model: People will be tripping over each other in an attempt to predict just when said game will break down and admit that it needs F2P.