Management often gets rewarded for new "launches", and rarely for things that already worked continuing to work. To some degree, so does the business (although a track record of things continuing to work over a long period has value, if anyone has a time horizon beyond the next quarterly report). Meanwhile, it is more difficult to measure productivity for maintenance work, because the primary work product is understanding. Managers with the skill and experience to recognize and compensate for this are rare. Developers are not blind to these incentives.