You're being down-voted (not by me) because your point is both cynical, and common as a caricature of management.
Employees need to feel safe because that improves their ability to focus on the job at hand.
Employees that do not feel safe spend time updating their resume, playing office-politics games to make others look worse, spend time with other employees (detracting them) to either spread rumours or get gossip.
In an unsafe environment, where the unsafty is internal, people don't "work harder" they work much less.
If the risk is external, then yes, people can pull together for the common good. When covid started our staff accepted huge pay cuts so that all jobs could bd preserved. They did a fantastic job, and all ultimately got back-pay, and all jobs were preserved. But that was "us against the world" - cuts included management, and salaries returned from the bottom to the top, not the other way around.