Prior to this lawsuit, Apple could bluff and say they would contract with Bing or some other search engine, and indeed evidence from the trial showed that Apple

Prior to this lawsuit, Apple could bluff and say they would contract with Bing or some other search engine, and indeed evidence from the trial showed that Apple would invite Bing to submit bids but internally was clear that no amount of money would be enough to switch from Google. One key piece of evidence showed that Microsoft had offered to give Apple 100% of its Bing revenue on Apple devices and that still wasn’t enough to overcome Bing’s lack of quality. If Google is removed as an available option, Apple can longer keep up the facade and will be forced to either suck it up and keep Google for free or give their users an inferior product. Mozilla tried switching from Google once and users hated it. Apple doesn’t want to piss off its users.