My personal issue with unions is I've seen the way my family members work places have acted through the fact that collective bargaining has given them the ability to leverage things such as years served as a way to dictate many aspects of how the organization is run. Additionally, it is very hard to fire people, where people can coast for years and still continue to get raises and even promotions.

Additionally, unions force costs to go up on many projects and revert any productivity gains that technology has provided. This prevents projects from getting done reducing the GDP impact of the larger industry even though certain people would likely get paid less.

Yes, for labor jobs, unions are absolutely necessary, but from my perspective collective bargaining presents many failures when it comes to coordinating large projects across multiple union groups, in addition to demoralizing high performers as unions as of right now have not adopted well to any sort of up or out promotion structure.