Fully recognizing that Apple's 30% is highway robbery, isn't Google's "only 10%" still fairly outrageous? This seems like more a 5% feature, since the app providers still have to provide all their own infrastructure to actually support the subscription.
This isn't a "processing" fee. This is a new kind of fee. It's a "platform access" fee. Apple sees value in the fact that they've cultivated a mass of users who are more than willing to repeatedly spend small amounts of money on content. I don't think that point can be overstated. iOS users buy a ton of content, and anyone with content to push wants access to them. Hence, the standard rules of supply and demand apply…
If Apple were to relinquish their price-match requirement (unlikely) or allow apps that had no external store references (more likely), they would not cause such an upheaval in pricing.