I use DNS to block ads when control over the HOSTS file is not available to the user. Works across all applications, e.g. browsers, apps, and requires no insta

I use DNS to block ads when control over the HOSTS file is not available to the user. Works across all applications, e.g. browsers, apps, and requires no installation of third party software e.g. extensions. I'm curious: do these ad blocking "solutions" operate as businesses? Do ad servers pay to be removed from blacklists? Pardon my ignorance.