In responding to a recent post over at Bullet Points, it occurred to me that the makers of sub based MMOs have an odd quandary. Every time they add content to a game for free, the value of a sub goes up since it buys access to more. A side effect of this is that if you are thinking about subbing to a game but can't decide whether to do it now or later, waiting until later will always be a better idea from an economic perspective. High value sub fee games such as City of Heroes/ Villains or year one LoTRO, where tons of content is added for free, suffer most strongly from this effect.
At the extreme are games such as Everquest II that offer "all in one packs," where the core game and all previous expansions are included free when you buy the latest expansion. From a pure economic perspective, every year that you put off starting the game adds enormous value to it. Compared to someone that has been playing all along, a late comer gets tons of content for very little money.
Compare the above games to a game like World of Warcraft, where new content is only rarely added for free, and a late comer has to pay for the client and every expansion pack separately. There is little incentive to put off subbing, because it won't get you much additional content and it will make the game more expensive to buy. If you are thinking about subbing now, you may as well because waiting doesn't get you much.
Even more extreme is a FtP game, where waiting to start playing gets you nothing. The same parts of the game will still be free, and you will have to pay exactly the same amount to unlock additional content. The only difference is that there will be more content to unlock, which will potentially make the game more expensive to have unfettered access to for a completionist.
The better value a game provides (in terms of free content) for an ongoing sub fee, and the more generous the handling of past expansions, the stronger the economic incentive for potential customers to put off subbing. Of course the flip side of this is that the more quickly a MMO builds value, the more quickly it will build up to some critical threshold where customers only mildly interested in it might do the trial. That is exactly what happened to me with Star Wars Galaxies. Seeing that I could potentially get half a decade of content for $20 was enough to get me to take it for a spin (even if it didn't stick). Which of the two effects is stronger probably varies from one customer to another, and how interested they are in a game to begin with.