The web sites in question can make their subdomains point anywhere they want. They can forward all their tracking info to the ad companies without any real tech

The web sites in question can make their subdomains point anywhere they want. They can forward all their tracking info to the ad companies without any real technical innovation. This fight is ultimately futile. The only real solution here is legislative. BTW, why do browsers not treat subdomains as separate entities for the purposes of figuring out what is a third party? Why don't they restrict things on the basis of IP addresses and skip all this complexity? One connection, one IP address...