The study polled over 2000 gamers and found that only hardcore gamers seemed to be interested in subscription-based models for MMOs.
On the other hand, the study found that "social, dormant, and leisure gamers all show significant interest in a free-to-play, microtransaction-based model." The study showed that 14% of gamers who weren't currently playing MMOs were more interested in trying one out if it was free-to-play, while only 2% of gamers were interested in MMO games requiring subscriptions.
According to Parks Associates' Michael Cai, free MMOs allow more players to try a game out, thereby allowing them to choose whether or not to spend their time and money on a game, as well as offering more freedom in determining how much time and money they want to spend on it.