After WW II, my father landed a job as an office clerk in the then new International Harvester Foundry in Memphis, TN. I don't know exactly when they went Union, but they were UAW. When I was a kid, Dad was a solid union man. A true believer. He made good money and I grew up as an upper middle class kid.
33 years later, Dad was now in upper management. He absolutely hated the union. They had a strangle hold on the entire company. Their unreasonable demands were hurting the company badly. Dad originally intended to retire at 35 years. But he saw the writing on the wall and pulled the plug two years early.
The following year, the foundry closed. It was actually cheaper for IH to have all their steel forging done in Japan and then ship those parts to American factories than it was to keep the foundry open.
Over 650 jobs lost, plus all the side vendors that kept the plant running on a daily basis and a major hit to the local economy. That whole section of Memphis is now little more than a ghetto.
1980s. Joe had a very successful fresh produce and garden store. Joe was a good friend of my wife's family and I knew him. He was at our wedding. Joe was a smart businessman, but not somebody you wanted to cross. He did the best he could for his employees. Maybe not a great job, but it was a decent living.
Anyway employees got to grumbling and voted in a union. They immediately went on strike. Joe went to the table with the union reps with a fair offer. The union people said "We don't care what you want. You'll do what we tell you!"
Wrong move!

Joe walked out among the striking workers and announced that anybody not at work tomorrow is fired! He did it too! Hired a whole new crew and went back to work like nothing had happened.
The union kept a picket line out by the street in front of his store for a very long time. The original union employees were long gone and the union hired outside people to picket the store. Customers ignored the pickets and business was booming. The union was trying to send a message. But after about three years, they finally gave up. Joe won!
1988. I was working as a mechanic for a truck leasing company. There were 20 of us working in the shop 24/7. It was a good job. Decent pay with pretty good benefits. One of the guys figured we should unionize. He actually got enough signatures to force a vote. This was the Teamsters Union. Management held several employee meetings and told us straight up that if we went on strike, they could farm out all the work we normally did and still make a profit. They would outlast any strike.
The teamsters OTOH never bothered to send anybody to talk to us. They sent one observer on voting day and he wouldn't answer any of our questions. The vote was 20 to 0 against the union. Even the guy who started all this voted against the union.
So, tell me again how good unions are?