I think the point is that if Google is not allowed to make such payments, neither is Microsoft (unless they want to risk the same lawsuit against them). Apple will stay with Google since a change would probably be unpopular with users. End result: Default search engines stay the same, but Google doesn't have to pay for it anymore.
I think this ignores Apple could still develop their own search engine, as they did with Maps, and pocket the ad revenue themselves.
They could, and they should, but they definitely won't. Similar to how they use just a ChatGPT anonymized wrapper for their "advanced AI features", they'll just outsource search to some big player as well.
