The author needs to clarify what portion of total revenue Google derives from ads, and then to break those ads out by service (Youtube, Gmail, Sponsored search), platform (desktop vs. mobile), and geography. Those stats probably aren't publicly available, but it would be good to have a rough estimate so we could have a more nuanced conversation around relative values rather than just one big pot of "ad revenue".

Otherwise, you're really just fumbling around in the dark, saying that monetizing mobile searches with such a low average daily click rate are a big problem for Google when the reality could be that they've never made much money from mobile search ads, especially in developing countries where they are adding the most users whose ad clicks are worth less because they have less disposable income than the average American or European. Similarly I'd wager that mobile search ads are a very small portion of Google's overall mobile business, and that Google never planned to make much money from mobile search in the first place, understanding that building out the app ecosystem and getting Android onto a ton of phones was more important in the long run.

People don't explore on their smartphones: they consume.

This as a cool thought experiment that could have been improved with more insight into breaking "ad revenue" into meaningful chunks to see whether or not Google actually cares about the slice considered in the headline: mobile search ad revenue.