I gotta call bullsh*t on that story. Sounds like a page from Apple's "sorry, you can't buy an iPhone today" playbook.
Ad revenue from free games is pennies per thousands of downloads. To make 50k per day you'd have to have tens of millions of downloads every day. The vast majority of them earn less than $100 per month (still a significant income if you live in Vietnam!). Just visit some of the forums frequented by these developers - a common complaint is the ad distributor won't pay them until they've hit some number like $200 in their account.
True, some of the more popular games such as Angry Birds have seen hundreds of millions of downloads. I doubt even they are making 50k per day from click-through revenue.