Of course all of that is just the deal with unions at the micro level - between the firm and the workers at that firm.
At the macro level unions are nothing but trouble and communism.
The big problem is the same as it is at the micro level - unions promote the layabout workers who have the most patience to get ahead, and discourage people with drive and a desire for meritocratic advancement.
This is exactly how you breed truly communist ideas, which is why commies and other crypto-commie ideological shards fucking love unions. It's just a step along their path.
(btw, Fascism is based on the fasces, which is literally a metaphor for unionization - so whenever you see a lefty who loves unions talk shit about fascism, just point out that all fascism actually means is "union" and ask them why they hate the concept of unity, this will fuck with them if you can pose it correctly)
Anyway, unions at national levels bring all of the problems of the micro level with them and when combined with government employment, mean you create permanent drains that promote larger and larger government to support their growth.
They become cancerous to a state and eventually come to control it. This is because nameless bureaucrats ultimately are the ones in charge of every state rather than figureheads of power. And if those nameless bureaucrats are unionized?
Well, you're half-way to communism friendo.
For the example here, look at Teacher's unions in the US. They leverage a lot of political power, do very little for actual teachers or aiding in the education of the youth, and yet consistently prevent educational reform because if you oppose them, they convince the public at large that you're endangering the future success of everyone's kids.
Nurses unions in the UK (for another example) are the primary driver of the Labour party there and are essentially one giant machine that shovels increasing amounts of money from the government into the NHS.