It doesn't sound like you have any actual first-hand experience with unions. I'll admit unions played a significant role in improving the workplace for everyone, and we should all be thankful for their contributions 50+ years ago. But they are now primarily self-serving organizations that exist for the benefit of the union itself.
Before becoming a developer I worked in hotels (as a banquet manager), let me give you some examples of the types of things unions now fight for:
* a dishwasher cannot wash pots and a potwasher cannot wash dishes
* only an electrician can change the batteries in a TV remote or change a lightbulb
* when it's busy your manager(s) cannot help you
* re-hiring of employees who were terminated because they were caught stealing or physically assaulting other employees
The better an employee is the less they benefit from a union. It results in good employees not getting paid as well as they could be and bad employees sticking around because it's difficult (or impossible) to fire them.
We could certainly benefit from the types of professional association lawyers[1] and doctors[2] have, but those are quite different than unions.
[1] https://en.wikipedia.org/wiki/American_Bar_Association
[2] https://en.wikipedia.org/wiki/American_Medical_Association