Once LLMs get fast enough at processing real-time images Apple (or anybody really) can just roll out a browser rendering engine that just masks all ads. It will take a few years but the browser ad-business is in it's terminal phase.
If we're just talking about image based ads it would be easier to simply denylist every image on a page and only render alt-text until the user clicks to reveal it. Worth noting though that Apple injects ads into the News app, which is just a webview, so it's certainly not them that will do this.
Ignoring that users care deeply about images so a browser that did this would be considered broken from the get go.