It's not hard to imagine spending that kind of money. Lots of people spend comparable amounts on alcohol, sporting events, concerts, tools, car mods, computers, collectables, board games, clothes, jewelry, gambling, whatever.
> exploiting psychology to extract money from people who make make poor financial decisions.
I've no love for Zynga and their shitty practices, but you could make the same criticism of people who have children. People will spend whatever they've got to be happy. $4000 per year is not an alarming amount unless you're ruining lives to pay it.