"There's another level of success, which is reaching a certain mass-market critical mass, which to be totally fair, only Blizzard has achieved completely so far," Steefel said in an interview published today.
"We think that we are the game that has the most likelihood of being the second to do that, but we're not there yet."
Turbine does not publicly release subscriber figures for Lord of the Rings Online, but maintains that the game is profitable, and growing.
Steefel's optimism about LOTRO's future stems from the Asian launches, the return of Tolkien to the cinemas with Guillermo del Toro's forthcoming Hobbit movie, and Turbine's determination to bring the game to new markets.
He expects the game will need to move beyond a standard subscription model in the long run. "This is a franchise that's going to continue for years and years and years, and there's no way that the singular, monolithic, USD 14.95 a month subscription model is going to last for years and years and years all by itself... it has to change."
Steefel also gave the clearest indication yet that Turbine's in-development console game is a version, or extension, of Lord of the Rings Online.