Word Lens is not something trivial that someone can replicate easily. It can take years to just create a good translation engine and it takes a while to write a good image recognition engine that can work in real time. If it were easy, we would have seen Chinese/Indian-made clones by now. Games, To-Do apps, Text Editors is what's easy and most prevalent in the App Store. Hard apps is what's rare. And Google's buying them up.