Ooh -- can I make silly generalizations, as well?
My personal favorite theory about why iOS makes more revenue in the app store, is that more Android users wildly mash at their phone screens with their giant, greasy potato-chip-dust-covered fingers in a Monster energy drink-induced aggro-fog and so are mostly unable to either understand or properly use their device well enough to access an app store and install stuff.
Or. Maybe people have different tastes for different reasons. And maybe the cherry-picked single data point that Final Fantasy III (which seems to have not sold very well at all) happened to be more popular on Android devices doesn't really mean much of anything conclusive (the PDF you linked to certainly doesn't have much to say about it). Maybe there are more "whales" on iOS simply because more users are comfortable using the platform and downloading apps, and given that app phones are damned near ubiquitous, both platforms will have smart-and-savvy users and rich (or poor or middle-class) "idiots." And everything in between.