"Are unions net benefit for the general public" and "whether reforming or abolishing the unions is the best course of action for the general public" are two separate questions. The unions could be beneficial (and still a reform could improve this benefit) or they could be harmful (but a reform could make them beneficial without abolishing them). The original claim was they are beneficial right now, in heir current form, but no actual proof had been provided.
> This is a great example of how unions can really work for their members.
I think this is way different claim than "unions work for the society". Surely, there are a lot of organizations that work very well for their members. Not all of them are beneficial for the society though (criminal gangs aren't, for example). In your third link, there is a power struggle between two sets of people - movie studios and writers. One of them has achieved transferring some money from the other, using the power of unions. But how is it good for the rest of the public? Unclear.
The case in Vox starts with "I liked the union" (the same claim as above) and doesn't get more convincing as it goes. The best the author can do is "When you stack up all the research and look at the broader picture, though, the net effect of unions — bad examples included — is good for the typical worker.". But that, again, is not the question we started with - I am not arguing that the union can be good for those who get more money from the deal. I want to see proof it's also good for those who don't. And the best is something like "reduces income inequality" - which frankly is a very weak evidence, since obviously absolute inequality is bad, and absolute equality is bad, but there are a lot of gray in the middle, and how do we know whether a particular union makes us closer to the good side than to the bad side?
Do you think Vox has ever written about how transit unions increase costs by mandating redundant workers and work against technology that could automate trains?
Do you think Box has ever written about how Detroit unions fought EVs and AVs and automation that could result in cheaper cars?