Yah, I keep tabs on that stuff. But most of my clients actually use Apple hardware for a few years now, and even if this update goes out tomorrow, and all iOS 11 users get it. iOS 10 users and below are out in the cold, and that accounts for 99% of my users.
And you know what it's like trying to use a feature even when 70% of users can take advantage of it, it's still a no-go. So Apple totally blew it on this one.
Apple has unusually high adoption (compared to Android) for new versions of their OS, I am not too worried. You can ship a service worker and it will not degrade the experience for users on older browsers.
