I think operating systems have changed. They don't interact directly with hardware much anymore, and the hardware is filled with SoCs all running systems of their own, sometimes with entire network stacks, communicating with devices and each other, collecting and processing data, often totally invisible to the operating system the user gets to work with. The operating systems most people use have gone from giving users control over their computer to being a sandboxed interface to manage files and some of what their computer is doing.