I thought of a new way to organize labor unions (this may have already been thought of). Instead of union membership being tied to one's job, how about allowing anyone to join the union regardless of what job they have? This might work better in the modern age; especially among young people who often don't stay at one job for more than a year. As people change jobs constantly, they could keep their union membership. Make it portable. Then they could still use some of the legal resources that union membership can provide, plus it would be a benefit to the union as there would be more dues paying members.
Union membership has been in decline for many decades. I have never been a big fan of unions as the solution, but do see them as having some merit. Looks like the unions are all but dead today.
I remember, back in the early 1980s, when getting into a union seemed very difficult. There were some apprenticeship programs for trades, such a plumbers and electricians, but one would hear that apprenticeship slots were hard to come by. To try and keep wages high, unions would constrict who got in. Usually union membership was based on employment, such as in the auto industry or working for the state. Wages were higher, but most people couldn't get into those jobs. Back then, it seemed like the unions didn't really care much about most workers who were not in the union; such as in restaurant workers and so forth. These days, it seems like what's left of the unions are getting better in their concern for the welfare of workers in general. They advocate things like affordable healthcare and raising the minimum wage. It may be a bit late, but modern unions seem less exclusionary than they were a few decades back, from what I gather.
Still, in today's "Uber" self employed work world, it seems like membership based on workplace is an out dated concept.
I can imagine some people asking how can a strike happen if union membership is voluntary, open to the public and not based on any one workplace? How can a strike happen if it's not closed shop all the workers unified in the union? I guess, the way it is now with practically no workers in unions, anymore, one worker can sometimes still create a stir by walking off the job. This can still get attention of management. What happens if, say, 20 or 30 percent of the workers, who happened to be members of a union, walked off the job. That would still have clout.
Union membership wouldn't have to be "closed shop," so there would be no need for the company to hold a vote to go unionized or not. Just a certain percentage of workers could join a union if they wished and carry that membership to whatever job they work at. Then, in some cases, groups of those workers could ban together using the union's organizing tools, if there was a need for that. A partial walkout as not all employees would be in the union. Better than no union, at least.
Maybe this has already been thought of; like trade associations. I remember, back in the 1980s, quite a few people joined Allied Arts Association, here in Whatcom County, as one of the benefits was getting a group rate on health insurance. That membership was open to the public.