Hello completely nonsensical statement.
Out of the dozens of F2P games I play, I've played at least half of them while paying nothing, or as little as 20 dollars total.
What are these F2P games requiring you to pay more than $15 a month? The ones I can think of that sell/restrict content generally provide all said content as part of the normal subscription.
So...I'm curious as to what these F2P games that force you to pay $15 or more a month. Last I checked, I'm never actually forced to pay anything. But hey, that's just me. I might just be strange or something.