> So ad companies' revenue gets shifted to Apple's app store, This presumes that everyone who is currently using add supported apps will start paying for apps

> So ad companies' revenue gets shifted to Apple's app store, This presumes that everyone who is currently using add supported apps will start paying for apps which is unlikely. There will continue to be ad supported software, it will just be less profitable. Likely at least some developers will shift to paid, but not nearly all.