The fundamental problem with labor unions is that they're stuck on negotiating with capital as an employer when the real threat is capital's corruption of the political system.

Consider where the wages of labor go. The major expenses are housing, taxes, transportation and healthcare.

Housing is artificially scarce. Zoning prevents new construction in areas with high demand, benefiting capital (i.e. landlords) who get higher rents. People who can't afford the higher rents have to live further from the city, increasing their transportation expenses (more money for Big Oil). Workers pay taxes but instead of going to some kind of UBI or anything else that would benefit workers, or just letting workers keep more of their money, most of it goes to things like the F-35 and buying the votes of retirees in the important swing state of Florida by enacting benefits which are really handouts to Big Pharma. And healthcare regulations are passed to make healthcare more expensive, i.e. more profitable, because of regulatory capture.

There's nothing in there that a labor union can solve by negotiating employee compensation with Walmart or Amazon. Because the problem is artificial scarcity, corruption and waste. At scale, if you negotiated everyone a raise, prices would just go up. Because everyone is still bidding on artificially scarce housing and paying for wasteful government programs and suffering the effects of regulatory capture.

But even when unions do try to lobby for something, it's typically just things to increase their own institutional power (e.g. trying to get Uber drivers into a union which is once again only negotiating employee compensation) instead of doing anything about the real problems that are sucking workers dry.