This has less to do with the technical merits of Plan 9 and more to do with the fact that nobody has ported a modern web browser to Plan 9 (there are some brows

This has less to do with the technical merits of Plan 9 and more to do with the fact that nobody has ported a modern web browser to Plan 9 (there are some browsers, but none with the feature parity of Firefox or Chrome). A slightly easier route to YouTube support for Plan 9 would be if somebody ported youtube-dl, but this work is also non-trivial. It’s the classic chicken-and-egg problem of adopting new platforms: the platform needs software to attract users, but developers won’t develop unless there are users or there’s a high likelihood users will come. It’s not that Plan 9 isn’t made for our world; it’s just that Linux/Windows/macOS/BSD and their software ecosystems are good enough for many users, and those who want to take advantage of Plan 9’s features have to contend with a lack of software in many domains. It’s similar to the reason I code in Python for my machine learning job despite the fact I’d prefer a Lisp or a statically-typed functional programming language: Python has a far richer ecosystem of machine learning and data science libraries.