Not too long ago, smartphones were considered futuristic technology. Now they are a staple in every country around the world and software companies are working furiously to develop all kinds of apps to make life easier. iPhone apps are very much in demand especially for mobile applications.
Given that the iPhone is so popular and has a large market share especially for the mobile platform, many software companies focus on iOS development. There is a lot of money in the iPhone application arena and apps can be used across a variety of devices.