The video games that are generating these big revenues are functionally identical to slot machines in their monetization schemes. There's one key difference. These games always keep 100% of the money. There's no way to get real money back. You can get cosmetic upgrades, various fake currencies, power-ups, and all sorts of other things in exchange for the real money. None of those things actually cost the video game company anything. They're just being paid to execute UPDATE statements on their database.
The effect of this is that a video game is a casino where no matter how lucky or skilled the player is, the house always keeps 100% of the real money no matter what. And we let children play in these casinos. In many countries they are largely unregulated. Meanwhile, the traditional casino that does occasionally pay out real money, is heavily regulated.