Not my original post.
They can do this easily, they can buy an existing engine and quickly release an mmo based on the classic look and feel of the original game. They name it Fallout Online: Prequel. They make it free to play with a low susbscriber cost. That secures the right, in the money and in the time frame. Then they use the small amount they make of prequel and build the first "expansion", the expansion would then replace all of the existing code with the new mmo they built, or they release the better MMO as a seperate game and maintain both communities.