I don't think that's true, precisely because the employee with a complaint can potentially increase their leverage significantly by educating and organizing other employees around the cause.
Your analysis seems to assume that there's some fixed percentage of employees who think some action from their employer is bad, and if that percentage is high enough, then all those employees could quit, which would either somehow signal to the employer that their action was bad or would damage the company so much that they would need to change their actions.
I think that's wishful thinking, and of course the percentage of employees with a complaint is not fixed and can be directly increased by internal efforts to organize. That applies not just to internal awareness, but also public awareness: note that we're only having discussions about cases where employees attempted to organize other employees.
Your analysis seems to assume that there's some fixed percentage of employees who think some action from their employer is bad, and if that percentage is high enough, then all those employees could quit, which would either somehow signal to the employer that their action was bad or would damage the company so much that they would need to change their actions.
I think that's wishful thinking, and of course the percentage of employees with a complaint is not fixed and can be directly increased by internal efforts to organize. That applies not just to internal awareness, but also public awareness: note that we're only having discussions about cases where employees attempted to organize other employees.