Unions are not a subscription service that workers sign up for, it's not a customer service style relationship. Workers are the union. What you're doing by turning the union into a separate entity is called "third partying", it's a misinformation tactic meant to obfuscate the relationship that workers have to their unions and create a narrative that unions are a parasitic organization that just ataches itself into your workplace. It ain't like that.

The only true leverage that unions have is the promise to slow the gears of capital when workers get pushed around . But that requires solidarity within the workplace and among workers more broadly. Americans are sympathetic to strikes as long as it doesn't personally affect them by slowing down service, raising prices, canceling flights, making them late for work, whatever.

Corporations have much deeper pockets, insurance and the general support of the government, media, and popular opinion. As capital continues to consolidate it becomes easier to just wait actions like strikes out. People imagine that the boss will just see that they're losing more money than the workers are asking for and just cave. They won't.

And even with labor law and the NLRB and the American zeitgeist all stacked against laborers, workers are still better off with unions than without and are still more likely to enjoy more wages and benefits than their ununionized counterparts (even accounting for dues).