Mobile games like these are designed with the help of addiction experts, each phase of the game is designed to trigger different emotions which builds up to constant frustration in the end.

The key is then manage that frustration by constantly showing the player that they could easily remove the source of the frustration by simply buying more resources.

This has to be done in way to keep the player feeling justly treated according to the rules of the game.

The game can't outright just steal your resources, but it can spawn in enemies to waste them and then limit how many resources you get in a specific time, that makes sure you don't blame the game itself but rather individual parts of the game.

Mobile games make more money than the entire rest of the gaming sector combined.

You sure Dolph won't be busy busting heads because he smelled crime or performing outrageous sexual experiments on his incredibly hot but skeptical female lab partner?

Freemium games are kinda hit and miss. But if it hit, the cash can be absofuckinglutely huge. And the misses aren't even that costly. So they try again and again. Good marketing is the key though, because in the flood of similar products the ones on top of the feed gets downloaded, hence i wouldn't be even very surprised if that marketing costs were greater than actual development of the game.