From what I understand from a friend in the field, even construction jobs that don't require you to physically build anything require a lot of long days on site and a lot of different jobs working in tandem to get everything right.
That friend also informed me that even a simple job can suddenly become a hair-pulling nightmare if someone who doesn't know what they're doing gets put in the wrong position of power. They also said that's not a rare occurrence.
Although that doesn't necessarily make the logic behind some of these whacked-out design decisions clear, these insights do make it easier to understand how they happened at all.