I only read this article, so I'm still fuzzy on the exact technical details, but couldn't a system like pipewire eventually be adopted into the kernel after it has proven itself adequate? Or is that not a thing the kernel does?
Probably not. Kernel handles the hardware. User-space deals with things like routing, mixing, resampling, fx, etc. Having that functionality outside of the kernel offers a lot more flexibility. Despite people chafing at the user-space audio API churn, it does allow advancements that would be much more difficult to do if implemented in the kernel.
