Despite open plugins, and mostly open end result file formats, the entirety of the media software world is built around proprietary software primarily for several reasons: Ephemeral fads have you making money in one big upfront push, integration of some new technique doesn't lend itself to open standards, or the fact that the actual bulk of paying customers are presumably working musicians with budgets, and that market is ultimately small. The side effect of this, much like radios, rc planes and drones, and many other hobbies, is that a collection of smaller product producing organizations have an even smaller, more even playing field full of smaller professionals and some amateurs. Some of the modular hardware producers have the right idea and provide free versions of their hardware as plugins as a marketing gimmick for their actual hardware. However, outside of the Linux world, the mystique of a proprietary salve that will supplant your creative block pushes people towards short sighted sales pushes instead of trying to lock in a give and take interaction with the broader community.

But I would love every thing that you list. I think things like PipeWire for better or worse are pushing things towards sanity, or least, better ideas for managing the mess in the open source world, which is decades in the making.