There is a reason Google paid close to 3 billon USD to stay the default search provider on iOS. They had several opportunities to pull their apps from the platform, but they never did. It’s not random. They acknowledge that Apple is not in direct competitior as far as their core business is concerned — unlike Microsoft. They can still be the primary search provider on iOS, but Microsoft would never let that happen on Windows Phone/Mobile thanks to Bing. In fact, there was no way to set the search engine to Google in Edge for a while - and the OS wide search never offered a choice.
Allowing Windows Phone/Mobile to flourish would have meant allowing Bing to grow - something Google can’t afford. As long as Apple doesn’t become a threat to their core business, I don’t think they are going to pull their apps. And even if they do, iOS has become too big to die like Windows Phone/Mobile.
And let’s not forget, the organisations charged with preventing monopoly will slap Google with antitrust lawsuits all over the world.