There probably is a market for a pay-for-play model that utilizes bitcoin as both an in-game currency and the only payment option. If anything, an entreprising small company with programmers who want to make money, yet work outside the fiat system could do this. Here is how I could see it happening and getting people "hooked."
1. Build free-to-play RPG, at least average play, have in-game currency drops equivalent to some low denomination bitcoin (like a satoshi).
2. Balance out the game initially so that the created in-game currency is roughly equal to that which is destroyed from buying in game items. Make the better items much more ridiculously priced. Charge in-game fees for excess play beyond 2 or 3 hours a day. Lots of one-time fees for "unlocking" capabilities, areas, etc.
3. Advertise game with something like, "Make digital money while slaying ogres!*"
* Restrictions apply on withdrawing funds to BTC (No more than once a month, fees (to pay Bitcoin network), etc)
4. Phase 1: Players check out the game, perhaps withdrawal a small amount or two (worth less than 1 cent USD) to verify that it works. Start to get the idea that they will at least "break even" on gameplay
5. Phase 2: Players start paying into the game in order to get access to better items and better areas with slightly more loot. They figure (incorrectly) that they could always grind their way for money to get it back in the game. However, the cost of better items is exponential, and the increase in treasure is more linear.
6. Phase 3: Ramp it up. Build a robust in-game auction system, but take a 5% cut off every transaction. Create in-game gambling. Have lots of optional, addictive activities that take a small cut.
7. Don't worry about growing in-game balances. A fractional reserve banking system has been created. Plan on never having to pay out the vast majority of players. LOL
8. If there's ever a run on the bank, declare yourself bankrupt, close up shop, and go live with Pirate40 on his island.
I spent way too long thinking about that. But there is way too much potential there. Just need some programmers willing to be paid in BTC.