> Why are all these people building different sandcastles when they could be working together?

Could they, though? What if upstream says ”thanks, but no thanks“ to your ideas? What if there are multiple, equally valid solutions to a problem, and you want to explore one that wasn‘t chosen?

Progress isn‘t linear, and not everything can be compromised on.

Just having more people work on a project, does not magically speed up development. You need leadership, a common goal, consensus, and focus.

If all these projects merged their efforts, that would probably result in a lot of lengthy discussions and infighting, rather than improvements.