As wonderful as money is, it's important not to make it your raison d'etre. There are too many developers creating rubbish heap games with the sole intention of churning them out as little cash bots using interstitial advertising etc in the hopes of getting rich. The actual game is considered a by-product of a stealth advertising strategy for the app stores. This is highly damaging and has an equivalent offender on the Amazon Kindle store where thousands of wannabe get-rich-quick authors publish sub-standard ebooks with awful DIY illustrations, dire stories and worse, all because they think that if their crap ebook can generate $1 a day, then they deduce that 100 crap ebooks could bring in $100 a day.
The genuine game developers always shine through, even if they don't create the next top 100 Appstore title.
Design and develop games because you love creating amazing fun gaming experiences and not because you want to emulate the Flappy Birds financial success.
If you enjoy statistics and money more than game development, you might as well give up now. The vast majority of solo / indie game developers won't make an annual income that exceeds what you'd earn flipping burgers in McDonalds.
Alternatively, stuff the money and just make the next best game because you want to. If it's a financial success, then that's an added bonus.