https://www.jofreeman.com/joreen/tyranny.htm
which describes issues that people struggle with to this day. When it comes to activism I think the most effective organizations I've been in have been "structureless" like that with a few people who lead because they are dedicated and have time and energy.
Personally when it comes to structure and the issues Jo talks about the cure (structure) is worse than the disease and once we start talking about Robert's Rules and bylaws and fundraising you are already losing people and going off mission. All the discussions about the perception (and somewhat reality) of "Class X of people is not being represented here" tend to turn into knock-down drag out fights, "Class X" never stepping up, and the ultimate reality of nobody being represented except for Robert and bylaws and fundraising.
It's not to say structureful organizations aren't useful but I would say organizations are basically right-wing in that they embody social hierarchy and if you feel your structureless organization is fun and exciting and making some difference in your bit of the world the way to save it when structure encroaches is to tear it down and start another one.
"Sustainable" groups tend to become what they oppose, structureless groups can seem to come out of nowhere, strike a decisive blow, then melt into the crowd.