This article is obviously talking with a US version of unions in mind. I'm going to give the French perspective because that's where I work, but I know something similar (and even better) exists in Germany.
Alongside traditional unions, which exist and are prevalent in traditional industries (e.g. railway workers are very unionised and often demonstrate/strike), there's also the so-called CSE(comité social et économique), a mini-union. It's mandatory for companies with more than 20 employees, and with more than 50 there's also a mandatory budget, time dedicated from employees, etc. There are elections to elect employee representatives, and they cannot be managers. They have a representative role before the 50 employee threshold, afterwards with the (mandatory) budget and time they also usually add other stuff like partnerships/perks/"fun" projects. The representative role is up to them (e.g. they can propose to management that X or Y be implemented, like profit sharing), but also within a legal framework (e.g. if the company wants to do layoffs, they have to consult the CSE on the layoff plan. If an employee is being pushed out/fired, the CSE can help (they can't block a firing, but they can provide guidance on rights, ensure things are done according to the law, etc.).
In Germany they take this a step further and at bigger companies (unsure of the exact threshold) employee representatives have board seats.