Why can’t iPhone assembly be automated?

The Information is out with a detailed look today at the myriad difficulties Apple has faced trying to automate iPhone assembly and the building of other products.
Quality assurance, iMac production, China (Image via Apple’s Supplier Responsibility 2020 Progress Report)
Joe Rossignol for MacRumors:The report claims that, beginning in 2012, Apple assembled a team of robotics and automation specialists at a secret lab in Sunnyvale, California to search for ways to reduce the number of worker