Manager should deliver on time and budget in order to keep their job. It is easier to do having performing team. Performing team consists of performing ICs. Easy as that.
On the whole, though, it's easiest to do that with low expectation setting. If I can convince management that what my team is doing is Very Hard and Very Important, my team will be perceived as high-performing. Unless the CEO is sitting in on sprints, except for extreme cases, they won't know better.
If you're in a large corporation, and your team does more with less, but your director constantly sees the output of another team, who gets laid off at the next layoffs? As a manager, how are the incentives split between managing your reports, and managing your director, the CEO, and the rest of the org?
This problem isn't specific to management. It's any time you've set up incentive structures, from teaching-to-the-test at schools, to how we select the CEO themselves.
- to find a way to keep their job through layoffs
- to find a way to move up to director
- to have fun at work
- to maintain work-life balance
... and so on.