The problem is that teams in large organizations are not run by the company owners themselves anymore, instead they are run by a middle manager whose job is to run the team.
The middle manager has no incentive to cut down too much on the team size, as that would risk his career, perceived social status, and even directly its job.
If a team of 10 all of the sudden becomes a team of 3, maybe there is no need for the middle manager anymore.
Also it does not look well on the CV to be a manager of a team of 3 instead of 10 people, so its not good for the manager career to cut down the team too much.
If the team size gets reduced a lot, the manager will be asked to do non-managerial tasks again, which would effectively mean a demotion.
Better yet: there are companies where a team needs to have at least N people in order for it to be assigned a manager. Otherwise it gets a "team leader" and several of those get assigned to a single manager.
N varies with the job, too. It can be as low as 5-6 in software development or engineering, and as high as 30-40 in administrative departments or poorly-automated production floors.
So if you cut the bullshit jobs, you also cut yours. No one does that.
How good it looks on the CV is also a factor, indeed, and often it's a barrier of entry, too. When hiring managers, many companies, including the ones that you'd think would know better, routinely demand a minimum team size, regardless of team performance. You can manage a team of 200 and run all projects into the ground and still get hired -- and yet get disappointed looks if you managed a team of 20, no matter how well it performed.
Managers offering to get their team trimmed because of lack of stuff to do is seen as a failure.
On one side the manager will be blamed for not being attached enough to its team, not being 'greedy' enough in general. On the other side the whole team will be blamed for not having come up with novel ideas and new expansion paths.
And as you say, even if the Level N manager is fine with that, it will look bad on the N+1 manager to not have a growing trend, and so-on.
Typically, at least in large organizations, the manager is interested in increasing, not decreasing, his budget. Since everything that happens in modern companies is very opaque (i.e. how much actual value is created is not clear for people outside a given business unit), the budget size/headcount is often used as a proxy for value. So, according to this logic, the bigger the headcount, the more important for the company the manager must be, so he can then negotiate a raise, bonus, or a promotion for himself. I agree with Michael O. Church here - managers in tech are mostly one-man PR firms (managing their own reputation). That sucks, but that's the result of our current workplaces in tech getting so complex that judging actual merit is close to impossible.
It's common for really large companies to use internal billing. So the IT department for example might charge other departments for their services and have to show it's a profit center. The problem with this of course is that it's also a monopoly, so this hardly incentivises better behaviour. In a situation where other departments can go outside the firm to get what they need, this is almost like outsourcing or divesting that department and it can act as a check on really bad cost:benefit ratios internally.
Wasting that money does bring the status of having a bigger organization, more direct reports, etc. Saving the money brings the questionable honor of being the manager whose team shrunk by 25% in a year.
The only corporations where efficiency still is key, are the ones where the owner-CEO is still able to keep an eye on the whole operation.
What I think people forget when we speak of monolithic institutions, be they institutions of learning, corporations, or even governments is that they aren't really monoliths. They're just made up of lots of individuals who are mostly just interested in themselves. So who is the person whose motivation is to reduce costs? Go look at the regularly flaunted bios and list of achievements of presidents of any major university. You're not going to find reducing costs anywhere in there. Instead you'll just find a whole slew of different ways they managed to find to spend even more money.
Here [1] is the president of Stanford's bio. Lo and behold, among his amazing achievements include 'Dr. Tessier-Lavigne worked with faculty, students, staff and trustees to develop and execute a ... a $500 million / 2 acre campus expansion project in the heart of Manhattan that broke ground in 2015.' Literally managing to spend half a billion dollars of other peoples money for a 2 acre expansion is, in and of itself, regarded as a noteworthy achievement.
But in practice, the reality is probably far more that most of the jobs do add value to the company, it's just relatively difficult to quantify (the related "as we're not an IT company, we should just outsource this department" mentality has never worked out very well...). Or taking the ludicrous Graeber definition of a "bullshit job", just because the employees would rather be poet musicians than credit controllers doesn't necessarily mean the world actually needs more street poetry of dubious merit and less timely payments.
And the given example of advising someone they can't bring their own furniture in without a good reason is a "bullshit task" which takes far less time than the alternative "bullshit task" of evaluating whether doing so might cause conflict, clutter or insurance liability issues, and auditing who owns which piece of furniture.
IMO this would be one of the biggest benefits of UBI -- money coming from actual people instead of risk-averse institutional investors.
As the company grows "too big to fail" it acquires power over society in general (and bailout money when needed).
That's a pretty good deal, and it can be the lifesaver when a company is struggling to be competitive.