My household probably counts as a high dollar in-game purchasing one. We probably boosted the numbers of some game developer.
Reality: a kids game had a $99 purchase option for hearts on the screen and my then 7-yo daughter not really understanding this was real money, spotted her mom putting in her password for App downloads and copied it to make about $400 of in-game purchases. This is nothing but a scam. There's no legitimate reason a game targeted at that age-group has a $99 purchase option other than to try to trick kids into spending money they don't know is being spent.
As the OP says - the quality of their product is terrible and once novelty wears off, apart from a few people with addiction issues their business model collapses.
Hate Zynga. Hate Groupon. Hate that they made such a big splash as tech IPOs yet will ultimately crash and the harm will spread to tech startups in general as the markets learn to distrust tech IPOs again.