If firing a bad performer is so difficult at so many places, then it must be a feature, not a bug. Otherwise the free market would've found a way to change this.
The thing is, everyone is judged by how much inefficiency they remove. This implies that for anyone to be successful, there needs to be inefficiency in the first place. This means that everyone has incentive to create inefficiency, which can be removed at a later time.
Imagine you have ten workers. They say "if we do ten things then the system will be much cheaper to run, but further improvements will be minimal". The most efficient thing to do would be to tell them to work on all things ASAP in parallel, but this means that you'll deliver a lot in the first year, and then very little later on. This makes you look bad as a manager. A much better approach is to artificially delay the tasks and force them to be sequential, one task a year. This means that from outside perspective, your team seems to be consistently delivering added value through entire ten years.
Moreover, imagine that you value all ten employees, but one day the upper management tells every team to fire at least two workers. At that point you'll wish you had two extra guys sitting and doing nothing because you'd be able to fire them without putting your own deliverables in danger.
Not to mention that as a manager, your prestige is proportional to the number of people below you. This means that you have incentive to create bloated teams that sit and do nothing, because having five good and five bad employees looks better on paper than just having five good employees.
In most companies, information flow is extremely opaque. If you're particularly unlucky then your direct supervisor might know your performance is bad, but other than that, zero chance of anyone noticing. And even your direct supervisor might either be too busy, lack knowledge, or simply not give a fuck, because he understands the business value of artificial inefficiency.
The thing is, everyone is judged by how much inefficiency they remove. This implies that for anyone to be successful, there needs to be inefficiency in the first place. This means that everyone has incentive to create inefficiency, which can be removed at a later time.
Imagine you have ten workers. They say "if we do ten things then the system will be much cheaper to run, but further improvements will be minimal". The most efficient thing to do would be to tell them to work on all things ASAP in parallel, but this means that you'll deliver a lot in the first year, and then very little later on. This makes you look bad as a manager. A much better approach is to artificially delay the tasks and force them to be sequential, one task a year. This means that from outside perspective, your team seems to be consistently delivering added value through entire ten years.
Moreover, imagine that you value all ten employees, but one day the upper management tells every team to fire at least two workers. At that point you'll wish you had two extra guys sitting and doing nothing because you'd be able to fire them without putting your own deliverables in danger.
Not to mention that as a manager, your prestige is proportional to the number of people below you. This means that you have incentive to create bloated teams that sit and do nothing, because having five good and five bad employees looks better on paper than just having five good employees.
In most companies, information flow is extremely opaque. If you're particularly unlucky then your direct supervisor might know your performance is bad, but other than that, zero chance of anyone noticing. And even your direct supervisor might either be too busy, lack knowledge, or simply not give a fuck, because he understands the business value of artificial inefficiency.