You mean their virtual character becomes happy because of the virtual sports car they now drive?
Tricking people to confuse their selves, possessions and lives with a simulation is some genius marketing. How did they pull this off?
You don't need to understand it, you don't even need to accept it for it to happen. You're discussing in bad faith.
How did they pull it off? It’s human nature…
Which design elements can one add/remove to such game to make a difference? Asking because it feels like a stretch to make an argument and also just how all things naturally are (opposed to designed deliberately).
And most video games aren't like this. You'll see a contrast in how addictive games are monetized compared to others. The tactics have been well-known for a while (World of Warcraft pioneered many of them in 2004-06), and in the past decade it's become a lot more common. GTA Online isn't totally an addictive game, but it seems to have a bit of that with the ingame assets.