As a former Union member in CA back you had to join in a closed shop and later as a member in a open shop where I became a union steward and then on the E board I will tell you that all Union are not good or bad, it depends on the Union and the Company.
I was promoted into first level management in 1980 and I had to sit in on more than one union grievance meetings sitting on the other side of the table, in the end I learned form both sides of the business on people and problem solving.
Many unions became corrupt after WW2, hence the work force here in the U.S. moving away from them, they sank them selves do to corruption, politics and graft
This country work force benefited a bunch early on in the 1920 and 1930 when the workforce was switching away form farming and going into the larger cities into manufacturing jobs in large industrial sweat shops that where dangerous to work in and paid very little back then EDITED: It was the labor unions who made working in those type jobs safer and better for the employees Many federal labor laws also help make the USA a great place to live and work in
Once some of the union members where promoted beyond their abilities in union management and started stealing, lying and cheating with the union members retirement and union dues the whole concept of the union helping make the members life better went into the toilet
Union member ship was at its peak in the late 1950 or the early 1960 at about 23% of the American workforce, this was before any government agency where allowed to become a union.
The last statistics I remember reading on current union membership here in America in 2010 was right at 7.5%, which 75% of them where some sort government employees, State, County, Federal, city, fire fighters law enforcement and school teachers and many other agencies which our tax dollar pay their wages
I saw a IBEW Union business agent steal a lot of money from the last local I belong to, I got involved in that local and starting showing other stewards and members what he and his wife where doing by inflating the monthly union hall operating costs instead keeping it honest He ended up changing his ways before he was charge for embezzlement and theft He seemed to think that because he had started that local in 1948 or 1949 and he had been the only B.A. in that local that it was his union, not the members. Two or three phone calls to the International union help change his mind about his ways of operating it from then on
In the end the unions management greed and corruption kill them in the private work force except for a few large industries like auto makers, some mining, some large trucking companies, some public utilizes companies and some other industries I can't think of right now