Free-to-play isn't a business model. Free-to-play is a marketing strategy. It's a way to get people over the hump of trying out your game. It gets rid of the friction that happens when you charge an upfront fee.
My kids download 10 games. They play them all for two minutes. They throw away the eight they don't like. Then they play those last two obsessively for a month. That's alien to those of us who buy a $60 game and play it for 40 or 50 hours. The discovery mechanism is completely social, and I don't think you get that genie back in the bottle.
