I completely agree, there are other methods of earning money without gauging your fan base.
King averaged something like $1 million a day a few years ago, at the height of the Candy Crush Saga situation. That is hard to not take notice of if you are a game developer or publisher.
Much like how much money Nintendo made during the height of Mario-mania in the late 80s though, many will try to duplicate but few will find similar success.