Certain markets are highly competitive for labor. A good example is software engineering. In those cases, because neither the corporation has a monopoly on their tech products nor does a union have a monopoly on labor the sector can be highly productive and everyone can get rich. In such a situation it seems pointless to have a union. Why would an employee want to be beholden to both his employer and his union? Unions, as well as giving their members some negotiating power, can also limit and burden their members in many ways.
Unions doesn't protect you in revolutionary times, so no. Detroits manufacturing sector was totally devastated even though they had extremely high unionization rates.
How about forcing businesses to be owned by their employees [1]? Instead of taxing the owning class and being paid UBI peanuts, you become the owning class and reap the rewards directly.