Hi, i'm the author. The point i was trying to make is that all we know is that we're looking at an incomplete picture. App store revenue is by far not the only way to make money with an app - i use CRM apps as an example, but many SaaS platforms have a supporting app, and we're not measuring that revenue at all. Neither are we measuing ad revenue.

But i agree, there's lots of anecdotal evidence either way :)