Most people don't, or only throw something like 5 bucks at games like that here or there. But some F2P games are pushing 10 years or more in existence, so somebody's paying to keep the servers running. The backbone of that industry is the small population of "whales" who spend their life's savings to get the superior rare new cosmetic or in-game currency to gamble their life away to maybe pull enough copies to max out their waifu. Then they'll use said cosmetic or waifu for about a month before the next super-ultra rare amazing once-in-a-lifetime hat or weapon comes along, or another waifu who totally eclipses their original one is released, then it's rinse, repeat ad infinitum until the whale is flat broke and their life is ruined. But at least they maxed out their waifu and got to the top of the rankings in the leaderboard.