I checked your link but as most people I’m not programmer, so we can’t check or even remotely understand what Google engineers does. On the other hand, what common people can understand is 'follow the money ́. Google makes most of its money on selling personalized ads, the more data they get on you the higher advertiser will bid.
It would make absolutely no sense, financially, for Google to reduce it’s tracking ability and let the user decide which ad they want to see or not.
And at the end Google is a business, money goes in, more money goes out. They could be doing what they claim to do right now, only to change in 2 years when all third party advertiser are bankrupt because they can’t use cookies anymore. That’s another possibility.