Android is somewhat challenging as instead of just two OS versions in the market usually there is 6 to 7 different OS versions and the new UI-UX featues that requrie particular attention. I could do the android UI-UX of each app by piecemeal but that falls apart as far as being able to maintain it as one wants time to devote towards updates as that is what pays the bills as far as paid IN-App Purchases.
Thus, one has to currate and clean-up a whole bunch of 3rd party UI-UX libraries with the goal of having this one stop UI-UX library that is backward compatible but forward looking as far as being maintainable when new UI-UX features get introduced by Google.
Than of course you are also currating and cleaning-up a set of utility libraries that allow you to modularize the parts of the android app so that you can put the apps together like you would lego blocks. Sounds simple, huh?
Mix that in with not one IT shop, Design Shop, or start-up understanding those goals or why those goals also benefit them as far as obtaining an android developer. Of course most of those are operating in the piecemeal website world still where you still can get away with such shoddy ill-planned software creation.