> You're not considering wedge issues?
Maybe our systems of government shouldn't have this weakness. This is what I was talking about when I mentioned the "strong indictment".
Based on your last comment I think our disagreement is less about what makes a democracy and more about what constitutes collective bargaining. I don't see a difference between the examples you cited and a worker at a private company telling their neighbours to boycott the company until working conditions improve. Both of these are individual actions and unless they're organized at a larger scale the word "collective" doesn't really apply to either of them.
Examples of things other than direct voting include campaign contributions, talking to the media, going door to door. In the case of teachers, you could talk directly to parents during meetings.
There are all kinds of ways to influence elections that go well beyond simply casting your vote.
You're not considering wedge issues? What if the candidate that would improve your working conditions also has a stance on an issue that you are strongly opposed to? For example, do you vote for the candidate who will give you a small raise but also disagrees with you on abortion? What if all of the candidates feel like siding with you would alienate more people than your voting bloc would bring?