Google has dropped the ball when it comes to penalizing websites that provide a bad experience (paywalls/login walls, ads, SEO filler content, etc) which makes sense when you realize that Google's revenue depends on ads so that downranking websites with ads (the aforementioned bad behaviors are often combined with ads) would be counter-productive to its bottom-line.
Apple would not have that limitation, and would be free to downrank websites at will considering their revenue doesn't directly depend on those sites. At the same time, if this becomes the default search engine on iOS it will force websites to comply with Apple's demands unless they're happy to lose out on a large chunk of potential customers with money to spend (as they've already demonstrated by buying an iOS device instead of Android).