Who needs 3rd party cookies when we control the browser itself?
Google just became aware that it no longer needs 3rd party cookies (which it can't control fully) when it can control the very tool people use to browse the web - all the data 3rd party cookies and tracking techniques attempt to use are already there - and without any chance for the user to block it (but using a different browser, of course).
Thereby the more control Google has on user data, the more advertisers have to pay Google for targeting through that data...