The claim was not merely that client-side protection "exists." It was that ads are not a privacy issue any longer, implying a ubiquitous native solution, which is false.

It's great that some OSes are trying to solve it system-wide but host blocking isn't viable as ubiquitous protection against this attack. It would just break all ads all the time, which ultimately would make the platform untenable for ad-based apps. What you want is something like the machine-learning Intelligent Tracking Prevention that Safari just rolled out, but applied to native apps. That is non-trivial.