Right now, Google has exclusive global contracts. A company with a product that's paid for Google's web search must use Google at every search access point and in every country they sell into where Google does business.
If Google's restricted from those contracts, local web search has a chance, user web search choice has a chance, the web itself has a chance.
Sure, Apple may keep Google in the US, but they might start swapping in Siri for some search access points, or swapping in ChatGPT search in others, or switching away from Google in Korea or Brazil or other markets with strong local services.
Who knows, maybe we'd have a compelling Apple Web Search today, like we have Apple Maps as an alternative to Google Maps, but that couldn't have happened because of these incentives. Take away the $20B+ a year Google pays Apple for that placement and maybe Apple provides a better service with more privacy protections and less spam. Maybe not, but if we don't change how this all works, we'll never know.
They've been doing this for years now.
AppleBot has been crawling away powering the Safari Suggestions engine.
"In lieu of the court ruling, Apple today announces the availability of Apple Scout and Apple AdSight. Apple Scout will serve as the new default search engine in MacOS and iOS."
"Markets were shaken today as Alphabet plunged 20%..."