I suspect that one could argue that all of the current poll options already exist and will continue to do so. It really depends upon your definition of "forum games". I feel that they would need to take place on a forum... Forums tend to have difficulty establishing themselves without some major founding element, such as a game about drunk dorfs. It is typically difficult to run a commercial operation within someone else's house... People will always form communities around projects and communities will always play and that seems like a reliable future for forum games. Any of the other options are possible and could potentially become major influences, but that all seems highly speculative.
And then there is the issue of things changing when they become commercial. It is certainly not universal, but it does raise the question of how much a forum game can change and still be a forum game...
They certainly do have value, but people generally host them because they want to. It can also be said that the participants also have value, I could certainly see people paying to gain access to players if there was a framework in place such that no other way to get them existed, some sort of totalitarian internet horror wherein all threads required payment to the world authority and allowing others to use your thread for their own project was punishable by death... I have nothing against anyone who wishes to sell their forum game, but I do not see it being a thing that has any prospects in the absence of a massive amount of ground-work setting up an environment in which it can be marketed successfully, to the extent that people would likely need financial backing just like most other commercial projects. It also becomes a bit messy when you are sellng a creative work which has contributions from others...
Ultimately, the game-host is free to do whatever they like, game-players do not have any intrinsic right to games. Likewise, hosts have no intrinsic right to players. That said. Web of Life is great and thus has an intrinsic right to players, where are they all? I am simultaneously plodding around in an uncomfortably empty room and terrified that I have somehow ruined it by hogging all the suggestions, or intruding too much into the character's personality or something... Well, I can but vote I suppose...
+1 Web of Life: A Drider's Tale.