It also undermines your leverage if you want to bargain with the company over things like a raise in salary. You also have less protection against malicious actions from your work.

That’s what switching companies is for.

This is sad. Do you want to stay with a company that wants to fire you?

Until I get a new job and land softly, yes.

I want to be the one dictating when I move.

Every company wants to fire you

Uhm, what? How do you mean?

Personally, I don’t worry about being replaced. It can happen, but I don’t believe it’s helpful to be stressed about it. The way I prepare for it is to try to learn new stuff all the time and keeping in touch with people in the same field.

I would not say that I worry about it. It is just that being indispensable in this way can come about by laziness if nothing else.

So I would spend effort to make myself worse off.

seems like you need to find a job with better management

It’s a fundamental problem of misaligned incentives between the employee and employer.

It is in the interests of the employee to have a more defensible position, even if it increases employer risk.

Which means you need to find a new employer. There are companies and/or managers out there that don’t have these misalign incentives, encourage best practices (like those in this blog post), and provide psychological safety. They exist.

The incentives are misaligmed at fundamental level. If manager could fire you while still getting the same job done they would.

Your best defence are your capabilities. Being “indispensable” means nothing if the company goes under.

Exactly. If you increase team productivity and your boss fires you for it instead of promoting you, then the company is doomed so why would you want to work for them?

Or: Given that most companies are horribly mismanaged, they completely fail to reward sensible behavior...

Quite often the high cost of firing someone is exactly the reason why the company wants to fire them. If you're someone who doesn't do things the way the company would like that isn't leverage; that's a reason to push you out.