So Google is giving Apple 30% of all in-app subscription upgrades to Google Drive?
I believe so, but I think it also depends on whether the subscription is managed through Apple's store. I subscribe to the WSJ online edition and have long before I bought an iPhone / iPad. But now I use the WSJ app quite a bit. BUT - my subscription is still billed via WSJ, not Apple.
I think it depends on how billing occurs. IMHO, I think Apple believes this competes or MAY compete with iCloud - and so are being obstinate. Instigram vs. Twitter anyone?