Unions, used for their original intent, are merely a tool. They were means of giving the employee a voice. However, over the past several decades, they have become outdated, corrupt and a menace to society... (much like the government in many aspects). If used properly, I don't believe a Union could be classified "bad" just like I don't believe guns kill- people do. So... I will rant a little more...
I believe the reason they are still around is 2 fold. 1st- $$$. 2ND- "tradition." I will speak about the 2ND point directly from experience in my family. My mother is a teacher in Kansas. When she was hired, she was not given the option of joining a Union. Rather, the question was "Which of the two do you want to join?" Then, she was required by the State to pay monthly dues to this Union that supposedly voiced her concerns. Over the course of 25+ years with this Union, she received about 5% pay increase (give or take based on the State's budget) and several $100 insurance cost increase- all negotiated by her "voice." She never had the opportunity to negotiate her own worth. Then, one day, she had a legal dispute with her school and a child's family. Instead of the Union coming to her defense, which was the intention of the Union Rep, the whole issue was swept under the table. Thank goodness she did not receive a reprimand. But the issue was never resolved to her satisfaction either. If this Union had not been in place, she would have A) had the opportunity to show her worth thru her supervisor/ negotiate on an individual basis her pay and B) had the opportunity to hire her own representation that would have come to her defense with a vengeance. Why did she go with a Union? Because it was what was done. There was no other choice. Complete BS if you ask me.