Sam, I respect your opinion but man, are you way off base about how Unions work and how management works. Let me see if I understand you.
In a perfect world, Company/Manager "A" would hire the best and brightest workers he could, fire only for just cause, pay a fair and adequate wage based solely on how much physical labor he performs, and all would be well with everyone. If the worker only pushes two buttons per hour on a million dollar machine that nets the company gross profits then the worker would be paid minimum wage. And, the worker who picks up pallets, tosses boxes, and does more physical work would be paid more, even though the machine operator has to know how to operate the machine, what tolerances to meet, how to set up and make changes on the machine, etc. After all, he is working his ass off; the machine operator is only pushing buttons. Either worker would never have to worry if he (or she) was going to be replaced as long as everything works fine and Company/Manager "A" makes an enormous profit and pays little if any benefits.
Of course, in your scenario, Company/Manager "A" would be entitled to pay what he thought was due the employee, give out benefits (such as vacation, sick time, number of work hours in a week, overtime, 401k, pension, etc) as he saw fit and to whom he saw fit, and the employee should be glad for what he gets because, after all, he's just an employee. Meanwhile, Company/Manager "A" reaps millions and millions in profits year after year, ignores labor laws, and can (and will) reward his friends and buddies, hire and fire as he sees fit, and discipline depending upon how his mood may be or whether he likes the guy or gal. Heck, he could even let the woman go who becomes pregnant or the guy who gets a long term illness because that just costs the company even more money.
Ok, even IF my appraisal of your perfect world is too far fetched for you, lets try this one. Suppose Company/Manager "A" has a great business for a long time. He's fair, treats everyone equally, and pays according to the value of the employee as well as to a reasonable scale for that type of labor. But, suppose that hard times fall upon the Company? Manager "A" decides that well, even though all the workers are doing a great job, he will keep the ones who he has been closest with or maybe even just those who are on his bowling league, or only the men, or only the caucasians. Far fetched? Not at all. It happens.
Why, he could even lay off the older guys who are getting close enough to retire and take their pension. You know - just close enough to retirement that they probably won't get another job but far enough away that the Company doesn't have to worry about the worker(s) drawing on the pension fund. It happens folks.
Or, the manager could simply decide that where before he had 5 people on a crew doing a set of tasks that he will cut that to 3 people, keeping the ones he likes (not letting go the last hired) and forcing those 3 to do the work that previously 5 people did. It happens.
In a Union shop, disciplinary action is defined. Layoffs occur by seniority. Wages and working conditions are negotiated and set in the contract. Benefits are defined and paid accordingly, not according to how the manager would like to make his own personal evaluation look. Workers are (as a rule) treated fairly because they know the rules that THEY have to abide by and what the COMPANY must abide by. There is no guessing, no management by personality, no gray areas. When a company can prove that they are on hard times, Unions can AND DO renegotiate to make the company competitive.
If you were to read the Union and Company trade magazines, you would see that far more new companies become unionized than those whose employees choose to drop from a Union's membership. This says a LOT.
Will Unions ever be perfect? Not as long as they are made up of people, who are as imperfect as anything. Will management ever be perfect? No - for the same reasons that Unions will never be perfect.
But will a Union ever be unnecessary? Only when management decides to treat every employee as if they belonged to a Union, in the good times and in the bad. Until then, there will ALWAYS be a need for a Union.