TL;DR - Starting a business is hard and most fail.
The NYC has posted an interesting article about the app store boom. The article focuses on a couple that bet everything on developing a business around making apps. While I agree with the articles premise that making a living on the app store is a very hard thing to do (see Zynga's collapse), the article failed to mention that any startup is hard. The majority of startups fail regardless of the industry.
As someone who has been following the app store for many years the gold rush period has long been over. Flooding the app store with bad apps is no longer a way to make money. Users expect apps to be much higher quality than in 2009. High quality takes time and money to develop.
Discoverability it hard. Even if the app is high quality and solves a genuine problem for the user, it may remain impossible to find. People complain about the app stores discoverability like this is a problem unique to Apple, but it's not. Discoverability is hard in any business. Having a great product is simply not enough. Potential users must be told about the product.
One positive for the couple in the article is the husband learned how to write apps. While the app store gold rush may be over, the app store is not going away. Users increasingly expect every product to have a corresponding mobile app. Mobile web works for some products, but users expect a quality that is still hard to reach with todays mobile technology. As Steve Jobs so famously said about DropBox, apps will increasingly become features of a larger product. Dropbox on the other hand has turned out differently.