Google has rolled out "Privacy Sandbox," a Chrome feature first announced back in 2019 that, among other things, exchanges third-party cookies—the most common form of tracking technology—for what the company is now calling "Topics." Topics is a response to pushback against Google’s proposed...
Because it doesn't protect your privacy (Google still tracks everything), but it gives Google an even stronger monopoly to make taking other actions to protect your privacy less viable.
The end game is still their web DRM pretending to be "security" to make it impossible for you to choose how a page is displayed to you.
Google doesn't track everything. The browser determines your interests locally; the only information shared with Google (and advertisers) is which broad topics you've recently shown an interest in.