You are absolutely right. The thing I do not understand is why people favour updated 1970s-style UNIX, e.g. Linux and xBSD, when more modern sophisticated late

You are absolutely right. The thing I do not understand is why people favour updated 1970s-style UNIX, e.g. Linux and xBSD, when more modern sophisticated later Unixes are right there for the taking, such as Plan 9 and Inferno. My cynical suspicion is that it's because they are just too hard to understand. I know that I struggle to myself. The conceptual model of '70s UNIX, and (to me) horrible primitive tools such as Vi, are easier to understand than the richer, smarter OSes of the '80s (Plan 9, with integrated networking, proper namespaces, and the whole LAN as your workstation) and '90s (Inferno, which also abstracts away CPU architectures and replaces C with something cleaner and safer).