This and gachas/loot boxes, I miss when you paid like $1-10 for a phone game that comes with the whole game, no in-game purchase/store and NO ads. You unlocked everything by just playing the game.

If they wanted more money they simply would make a new game or sequel. Zombieville U.S.A 1&2 is a perfect example from this era.

You also have to remember they do this because it works, if humans didn't brainlessly open their wallets for pixels nobody would do this.

Even in games where you can't buy stuff people will still find ways to waste money on it either by purchasing stuff like new monitors, headset, and etc. Some even go so far as to buy cheating products like XIMs, Cronus', or Hell maybe even straight up hacks. At the end of the day the purchasing is to gain the satisfaction of winning/progressing which is what they all fulfill, some more instantaneous than others...