Honestly I’m surprised Google hasn’t offered to buy Truth Social for a few hundred million just to make this little antitrust problem go away.

From TFA: "Until today, Google was still planning to roll out a dialog in Chrome that would prompt users to turn off third-party cookies in favor of Google's updated solution. […] …Google won't be pushing that cookie dialog to users. You can still choose to disable third-party cookies in Chrome, though."

There's no reason they couldn't allow add-ons to do it: but instead with manifest v3 I think it is impossible to do it in a general way isn't it? Like with the other ad-blocking you have to have a hardcoded number of rules you can define for blocking cookies in the requests as well, at least through the declarativeNetRequest API.

Maybe it is possible for through one of the cookies APIs, but the cookie's API has race conditions where the site can still sometimes see them from what I understand and redirects can activate before your extension gets a chance to respond.

And then of course extensions don't even run on mobile and that isn't an accident.

I do disagree with your cause and effect though, they have gotten blocked from replacing third party cookies with privacy sandbox because it replaces a standard everyone can use equally with a Google-controlled system. They could have cited the industry standard to block third party cookies in other browsers and done so without a replacement, the reason they are being prohibited from doing so is because they are motivated to maintain data access for themselves via privacy sandbox.

You can read countless statements from the Chrome team about Privacy Sandbox where they state how vital spying on users for ad targeting is, they've never "wanted" to remove doing so.