This. It would quickly devolve into a power struggle of who could amass the most strength. You only have to sample the mob era to see what would happen, where shop owners for example were paying for protection. In the absense of any form of control there will always be people that will take advantage and sway others to their cause.

Yeah, but police units and private security firms are a form of "gang", just with different pay masters and accountability.

Notably accountability to the people (in principle if imperfect in practice), which is an important distinction indeed.

Oh the greeks! Great application of the quote.

https://en.m.wikipedia.org/wiki/Horror_vacui_(physics)