I recommend you get a copy of Basic Economics by Dr. Thomas Sowell. Read it. It's one of the best books on the subject I have ever read, and that's after taking economics in college. It will help you understand why what you wrote isn't true.
I don't mean to bash you or anything, and I'm sure that you're completely sincere in your belief. But with the probable exception of workplace safety, unions have done little that normal economic pressure wouldn't have accomplished. And their overall effect on the economy is a very clear negative.
In our day, the primary goal and effect of union labor is that workers are paid more than their work is worth. In a union shop, it's harder to fire those who need firing. It's nearly impossible to reward better work with better pay. Union goons intimidate, harass, threaten and even assault those who don't obey their wishes.
I work very near a number of union shops, though my current employer is not, thank heaven! I know very well how unions work and what they want.