> Everything you just said could be equally said about worker's unions, so why do we have worker's unions either instead of just using the government?

Why not ask the reverse question? “Why do we have a government instead of just having a workers union?”.

This is actually the political project of anarcho-syndicalists [1]: workers could self-organize the production and the collective life through democratic federalist instances. The idea has been theorized since at least 1906 in the Charter of Amiens [2], an historical text of syndicalism [3]: https://www.marxists.org/history/france/cgt/charter-amiens.h... where we can read “the union, today a resistance group will be, in the future, a group for production and redistribution, the basis of social reorganization.”.

At least in France, the biggest workers union (CGT) is still organized in a way that would allow this, by having both geographical and per-industry-branch instances (sorry I lack the proper words to describe this in English).

It is also what the Spanish CNT did during and after the Spnish Revolution of 1936 [4,5].

[1] https://en.wikipedia.org/wiki/Anarcho-syndicalism

[2] https://en.wikipedia.org/wiki/Charter_of_Amiens

[3] https://en.wikipedia.org/wiki/Syndicalism

[4] https://en.wikipedia.org/wiki/Spanish_Revolution_of_1936

[5] https://en.wikipedia.org/wiki/Revolutionary_Catalonia