how the original developer doesn’t/shouldn’t have to do everything – others can contribute (to me, a key concept in open source)
how interested/engaged users can be an important force in the direction in which a software application or tool goes forward

Dave Winer has written about this many times:

The magic of working together

Key concept of the open web: working together

Working together means this: If someone else has a good-enough way to do something, rather than reinvent what they do, incorporate what they do into what you do.

Working together (SOTN 2018)
Working together in 2019

I have tried to follow that second point in several ways:

My blog uses WordPress, I did not develop my own blogging tool
I use River5 as my RSS reader engine
I use RiverBrowser to display my own rivers of news

I document and evangelize how to create your own rivers of news
I document how to use tools like River4 and 1999.io

I help others set up these tools

I am getting ready to start working in the computer music area again after a long absence, and I am reviewing available tools to see if they fit the areas I am interested in. In that way, I am trying to practice the concepts of working together as I have outlined above.
Anyone want to work together with me? Let me know!