1. Google isn't relatively safe. They are paying rent to Apple just for default. And while the cost per user has been flat over the years, ( growth coming from total active iPhone / Apple user ). Apple may raise that cost, taking another slice form Google.

2. This has already happened. Amazon's Ads is making more profits than Amazon E-Comm itself.

It is nice we finally have some decent discussion on Ads. Rather than the usual HN rant about how all ads are evil. Or Internet should be free of Ads.