Remember that Firefox has at least a 3% marketshare. Safari has somewhere in the neighborhood of 20%. If websites are willing to go Chrome-only in that environment, permanent holdbacks won't change anything for those websites.
Particularly not if the solution to those holdbacks is "reinstall your browser and the holdback will probably go away." Which... they'd need to be unless Chrome starts tracking users to figure out who should have what holdbacks :)
The only way that holdbacks matter is if they affect 100% of Chrome users -- ie every single one of your customers/readers will at some point not send you attestation at some point for your website. And even then... telling them to refresh the page becomes a problem.
But it it's only a subset of users, then just banning 5% of users (especially from ad-supported platforms) seems perfectly feasible for a company and would probably be a preferred solution for some of them.
----
User: "Hey, for some reason when I browse Reddit nothing loads."
Support: "Yeah, very rarely a new Chrome install will do that. If you create an account and sign in, and then you send us some verification documents like an ID so we know you're not a scammer, then you'll still be able to browse. Otherwise just reinstall Chrome."
User: "Is there anything else I can do?"
Support: "No, we have to protect our ad integrity. If reinstalling the browser doesn't help, contact Google about it."
----
> Instead, you could create 20 separate top-sites and load them all in tiny iframes. :)
This too :)