Why doesn't Google reduce developer 30/70 split?

Like Apple, Google has employed a 70/30 split deal on Google Play app developers for 'operating costs.' My question is, why dont they lower this to 90/10 or even flat out 100 for the developer? The advantage would be increased money to developers which would be very convincing in getting app and game to developers from iOS to transfer, or even bring their apps to android first.

It seems they're clearly capable. I mean, they're willing to store 20,000 songs per user for free within Google Music; the operating costs and storage clearly are not too much of a problem for them. They already give away many products for free that lack significant, if any at all, advertising.

I theorize that Google knows that if it did lower this price, Apple would likely do the same in order to compete. Eventually, they would each go down to 100 percent to the developer, and would simply end up in worse situation for both companies, although a better one for the consumer. It's almost a kind of non-communicated price fixing. This is only a theory however.

So tell me what you guys think.