iOS vs Android app size

Does anyone have a credible explanation of why Android app updates are so much smaller than the same app on iOS?

Take a look at this page

Thanks Andrew a great read about what Android is doing to reduce file size. I might even turn on auto updates based on that. Does anyone know if Apple has something on the way to assist to reduce the app update size for iOS? I wrote an article a while back titled Is Microsoft killing me (and my network) with LOVE? which is still happening to my iPad at an alarming rate.