This Youtube video makes a good case that sub fees are not required to make MMOs profitable.
And while I don’t know whether Runes of Magic is profitable or not, the game’s servers seem quite busy, and they don’t charge either a subscription or a box fee. Their store prices seem quite reasonable to me, and I have no problem spending money in it. Plus, they offer the ability to buy store currency with in-game cash, making it entirely possible if you have the time to devote to making gold to buying store items without spending any real world cash.
More and more I’m seeing fewer reasons for MMOs to charge sub fees, especially on top of the box fee and cash shops. If they want to charge me a subscription, fine. But don’t make me also pay for the initial release and then sell me more content in the cash shop.
As an aside, Guild Wars 2 looks gorgeous in that video.