I'm confused; where is the difference in revenue coming from if you're selling the same product to the same number of people on each platform?

Oh now I see the confusion. No the cut is about the same, it's the platform itself as in its users. I don't know what it is but I suppose they just tend to spend money and click ads less. I can't pinpoint the exact reason but many other developers have experienced the same trend.

Exactly where you just stated yourself... the platform.

As in, Google takes a bigger cut?

No, both Apple and Google take 30%.