For now, you can simply block these subdomains in the ad blocker of your choice. The fundamental risk to ad blockers that these pose is that there will be too many subdomains to block in a list of reasonable size. But really that's not fundamentally different than other techniques like serving ads and real content from the same server, which has been happening for years.
(In theory, a site might generate new subdomains and DNS responses for them on the fly, making this approach unworkable. In practice however, most sites have moved entirely to HTTPS, which means that unless you give your ad host a certificate for *.yourdomain.com, all the subdomains have to be known in advance and show up in certificate transparency logs, making them easy to block.)
(In theory, a site might generate new subdomains and DNS responses for them on the fly, making this approach unworkable. In practice however, most sites have moved entirely to HTTPS, which means that unless you give your ad host a certificate for *.yourdomain.com, all the subdomains have to be known in advance and show up in certificate transparency logs, making them easy to block.)