I've spent a fair amount of time and energy working and researching in this area. I'd agree with most of what you are saying. To point #1 I worked on a project that had almost the exact same design you mention (collaborate, git versioned edits of learning modules, etc.) - the biggest problem is the mounds and mounds of red tape and regulation that stifle any truly innovative solution. There are some movements for high school materials that are tackling parts of the problem (see: https://www.ck12.org/student/, https://www.khanacademy.org/), but it definitely needs to be on a much larger and national scale and extended to universities. I think, most all undergraduate courses could be done this way. If someone with enough leverage could ever push it through it would virtually completely remove textbook, materials, and lecture costs from the system and if done right, provide a treasure store of knowledge.

To #2 This is already a technique in education research its called flipped classrooms (https://en.wikipedia.org/wiki/Flipped_classroom).

To #3, I'm sure there are organizational structures you could implement that would augment every students network - there's a lot of stuff from management science you could try out.

Overall though I found it extremely frustrating trying to innovate in education because you really need to be able to implement radical changes but there are so many regulations at every level that you have to creep forward, hoping for minor incremental improvements when what you need is complete system overhauls. This was extremely frustrating for me.