In a very real sense, the F2P business model only really works if the game is popular amount non-paying customers—otherwise, what would motivate whales to get into it in the first place? A whale-based system pretty much guarantees a product that's as widely accessible as possible.
Of course, it has its own massive ethical issues; I am no fan of the practice. (Not least because the people spending the most money aren't always the ones who can afford to spend that much!) But it does neatly invert the dynamic and uses the top 1% of spenders to finance something primarily enjoyed by the 99% who spend little to nothing.