I think it depends a lot on what you mean with "being at the leading edge" of mobile app development.

Programming an Android app that works isn't that hard. On the other hand that doesn't mean that you understand everything there to know about Android app development.

I remember from my informatic A lectures at university which were in Haskell that at the end of a semester some of the students still didn't understand the concept of recursion.

Someone without a math background or computer science background is probably not going to use recursion for problems that are neatly solved with it when designing his app after learning Android programming with the standard tutorials. For a programmer that simply considers principles like recursion common sense it can be very hard to estimate how much time someone without a background needs to learn the concept.

You can program in Android without knowing exactly when a given object will be garbage collected. Multithreading can be complicated. Someone with years of experience in developing Android apps will likely outperform a nonprogrammer who spends a year learning Android but that doesn't mean that the second person can't find work as an Android developer.