Unions have always been a two sided issue. But unfortunately the basic concept has been usurped by the Socialist/Communist idea of worker solidarity and communal sharing . .
The good side (if there truly is one) is that back in the early 20th Century (1910-15) the Mines in this country and some industry saw what the railroads had done in the mid 19th century with imported labor . . And they imported the largest percentage of theirs (98%) . . Labor organizers saw opportunity and began organizing small groups and then starting strikes . . By 1913, in Colorado, the strikers were fighting the company security forces and the Colorado Governor (and the Governor of Michigan) had called out the militia and established martial Law.
This took several years to iron out but eventually the mines in both colorado and Michigan were unionized . . After that most heavy industry surrendered to the unions simply to keep from repeating what had been seen in Colorado and Michigan.
Up until the late 60's the Unions boomed and enjoyed huge membership, which in turn, generated large amounts of money. The Unions held large sums of money for the member's retirement funds and they bought politicians with portions of that money.
Then, several of the larger National Unions invested in Las Vegas in the mid 60's, and the more they invested, the more the mafia (who literally owned the casinos at the time) stole . . which, in a very short period, literally bankrupted the Teamsters, and most of the AFL/CIO affiliates.
Most unions sought refuge from their pension obligations by a new act created by the unions and put into law by bought and paid for Politicians, that obligated the Federal government to come in and pick up those retirement payments for about a dime on the dollar . .
Then later on, in 2005, the UAW was seen as the major cause for the impending bankruptcies of both GM and Chrysler . . Ford had similar problems but managed to force the UAW to work out a feasable plan to keep the company liquid . . Obama came in a took GM and Chrysler away from it's stockholder Owners and literally gave them to the UAW, at your expense. (about a $16 billion loss when the last Federal GM stock was sold last year)
And today, Union membership is shrinking due to bad policy and the shrinking jobs market . . You can't make a robot pay union dues . . And most of the people working in the automobile plants in the South don't have complaints about their jobs or the workplace, so have no use for a union that would do no more than take dues out of their paycheck to support politicians and political agendas they don't like.
Bottom line, in 1913, there might have been a need for organized unions, but the fact that they have always been a subsidiary of organized crime, or the fall guy for the same, the world would probably be better off without them . .