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?
Maybe our systems of government shouldn't have this weakness. This is what I was talking about when I mentioned the "strong indictment".