Basically Google would immediately use all of their properties and muscle to wrest control of iOS. And then why even bother to have more than one platform.
Apple should stick to making top notch hardware and software for their phones. Just allow users to run a real web browser as well.
On the other hand: Chrome only became so popular because of their shady propagating of the software. Through freeware installers etc. Something you can prevent very easy on a Apple phone.
Also: the market is not so big. Even if they'd "take over" iPhone, it wouldn't make a big difference on the control they already have.
I don't believe they have ever been limited in porting, but have decided the performance hit for using their own javascript engines (or compatibility issues in leveraging Apple's) aren't worth the effort.
One for Safari and one for the rest.
Websites saved to the home screen use UIWebView's engine — but that's not the discussion, the discussion is about browser apps which can and do use WKWebView.
For crappy aid, I only remember iTunes on Windows.
What the... Was that...
This is nonsense. Safari is the only mobile browser available on iOS, so if you're sorting by mobile available per platform, then of course it's the "best [of one]". If Chrome and Firefox had the opportunity to bring their platform fully to market on iOS, there would be some real competition there... They could still do what Android does with displaying any in-app web rendering like Android System WebView, while allowing users the option to use the same browser and experience they're used to on their desktops.