Windows Store App making $30,000 a Month

There are iOS apps that are making $ millions.
Likely there are some such Androids apps, too.
Windows (8/RT) Store apps are still catching up,
but there are some some success stories like this:

“Windows 8 Brings Me $30,000 a Month,” Says Happy Developer

Since this app was making money on adds, and there are rumors of add rates going down, it is not clear how long this would last...