Some cities need traffic lights because they have traffic lights. If one traffic light goes out, it causes a traffic jam. But sometimes when all traffic lights go out, say due to a storm, traffic flows better than before.
Some buildings need air conditioning because they have air conditioning. Because they were designed to be air conditioned, they have no natural ventilation and would be miserable to inhabit without air conditioning.
Some people need to work because they work. A family may find that their second income is going entirely to expenses that would go away if one person stayed home.
It’s hard to tell when you’ve gotten into a situation where you need something because you have it. I had a friend that worked for a company that sold expensive software development tools. He said that one of the best perks of his job was that he could buy these tools at a deep discount. But he didn’t realize that without his job, he wouldn’t need these tools! He wasn’t using them to develop software. He was only using them so he could demonstrate and sell them.
It may be even harder for organizations to realize it has been caught in a cascade of needs. Suppose a useless project adds staff. These staff need to be managed, so they hire a manager. Then they hire people for IT, accounting, marketing, etc. Eventually they have their own building. This building needs security, maintenance, and housekeeping. No one questions the need for the security guard, but the guard would not have been necessary without the original useless project.
When something seems absolutely necessary, maybe it’s only necessary because of something else that isn’t necessary.