As the "agent web" progresses, how will advertisers actually get access to human eyeballs? Will our agents just be proxies for garbage like injected marketing

As the "agent web" progresses, how will advertisers actually get access to human eyeballs? Will our agents just be proxies for garbage like injected marketing prompts? I feel like this is going to be an existential moment for advertising that ultimately will lead to intrusive opportunities like this.