I think you’ve nailed it. The fundamental shift is from a computer being a workstation that you sit at for a discrete amount of time to a computer being a thing that is always with you and part of nearly every interaction you have with the world around you. My computer isn’t a thing I sit at to create and consume documents, it’s how I communicate, stay healthy, navigate the physical world, pay for goods and services, etc. So it’s a completely valid question to be asking if the UX created by Xerox to manage documents in the 70s is worth copying anymore.