I'm not sure how useful this is going to be if you only read portions of the replies.
Unions negotiate in advance. They set up multi-year contracts between employees and management. These often involve limitations on the company's ability to lay people off, or otherwise meaningfully change employment conditions.
They're not unlimited, and they don't go forever, but it tends to mean there's a lot fewer "surprise! you're all fired tomorrow!" scenarios, because there's contractual protections in place that companies won't give individuals without bargaining power.
Again, unions aren't magic - they can't prevent all layoffs. They can make them harder to do, and they can protect employees better during one.
If the company isn’t competitive and can’t pay their negotiated rates - they file for bankruptcy. When has a union ever protected workers when a company was in distress? The auto industry? The airline industry? Flight controllers in the 80s?
> Investment bank William Blair & Company estimated that the strike likely reduced Deere's output by between 10 and 15% for the fourth quarter of 2021 and the first quarter of 2022.[29]
The strike led to an increase in the already-inflated auction prices of used Deere equipment such as tractors and other used agricultural machines.[30]
Unions negotiate in advance. They set up multi-year contracts between employees and management. These often involve limitations on the company's ability to lay people off, or otherwise meaningfully change employment conditions.
They're not unlimited, and they don't go forever, but it tends to mean there's a lot fewer "surprise! you're all fired tomorrow!" scenarios, because there's contractual protections in place that companies won't give individuals without bargaining power.
Again, unions aren't magic - they can't prevent all layoffs. They can make them harder to do, and they can protect employees better during one.