My ideal in this arena is employee-owned enterprises, but minus that unions are the next best bet. There simply is no reason, imo, why employees should not have a say in their employment, and these "right to work" laws and court decisions are simply union busting-- that's the reality.
Since all employees are affected through the collective-bargaining process, to have dues being only optional makes no logical sense whatsoever as a rising tide raises all ships. It also can lead to more union-busting tactics, such as offering those who don't join the union higher wages and/or better benefits than those who do join.
According to an old FBI stat I learned many years ago, there's an estimated four times more money ripped off each year in white-collar crime than blue collar/"street" crime. Unions, otoh, can monitor some of these potentially illegal activities. IOW, if I'm a corrupt businessman/woman, I certain wouldn't want unions. Also, just a reminder that under national laws passed back in the 50's or 60's, the fed can monitor union votes and activities.
Over all my years of working, I've worked in both union and non-union places, and I much prefer the former because of the fact that I had at least some job security as long as I didn't screw up. Once as a teen working in a gas station I got fired for stealing money-- except that I didn't. My guess is that another employee took it. But besides being fired, my week's wages were cut by half, and I had no recourse but to accept it because I would have had to take it to court with all that would involve, including $. Had I had union representation, assuming the union would take my case up, the owner would have to put forth evidence that it was I who took the money.
The bottom line: the wealthy and corrupt owners don't like unions, but Americans who truly believe in democratic values for all plus having a middle class should. IOW, do we want to be just pawns or do we want to have a say? Yes, we can quit a job if we don't like the conditions, but then so can owners and CEO's if they don't like workers having at least some say in their employment.