Ina Fried, writing for Axios:

On the cutting board: Pushed into 2019 are a number of features including a refresh of the home screen and in-car user interfaces, improvements to core apps like mail and updates to the picture-taking, photo editing and sharing experiences.

What made it: There will be some new features, of course, including improvements in augmented reality, digital health and parental controls. In addition, Apple is prioritizing work to make iPhones more responsive and less prone to cause customer support issues.

This is a very good decision. iOS and macOS are currently very buggy and they are in need of care and polishing.

Also, I have not found a single reason to use AR yet.