After all, most people on mobile spend their time inside apps, probably from some Google competitor like Facebook. Within these apps, they click on links, which increasingly load inside webviews; the framing app collects info on where people go, and uses this to sell targeted advertising. Facebook is a king in this space, and is now the second largest server of internet display ads, after Google.
Google's assault on Facebook's encroachment is twofold: drive people to Google's apps like the Google Now Launcher (now the default launcher on Android) or the Google app present in older versions of Android and available for iOS, and deploy the same content-framing techniques from their own search engine webpage on mobile user-agents, where the competition is most fierce, and they can also position it as legitimate UX improvement -- which, to their credit, is largely true, as bigpub content sites on mobile were usually usability nightmares and cesspits of ads.
I understand that the author and quite a few others are peeved at this behavior and that there's no way of turning it off. But it's really not in Google's best interest to even offer the option, because then many people will just turn it off, encouraged by articles like the author's own last year where he was caught off-guard and before he gained a more nuanced appreciation for what's really going on.
The bottom line is this: Google is inseparable from its ad-serving and adtech business -- it is after all how they make most of their money -- so if you are bothered by their attempts to safeguard their income stream from competitors who have a much easier time curating their own walled garden, you should cease using Google Search on Mobile. There are other alternatives, who may not be as thorough at search, but that's the cost of the tradeoff.