I worked on that report! (Throwaway because, well, my real name is on the second page...)
The lack of meaningful technical planning was a big part of it, and so was the contract-awarding math, but I think the most striking - and generally applicable - behind-the-scenes stories were about what happens when trust breaks down at a human level. The city's internal back and forth on approving and then un-approving a subcontractor at the beginning meant that the GC was more likely to work to the letter of the contract when things went wrong later, instead of collaborating to solve problems. The one positive thing the city eventually did to get the project moving forward, according to all the information we got, was put someone with some amount of authority on the ground to talk to people.
Rereading the report now, all of these facts are in there, but I wish we'd found a way to stress this part more. You see the same thing in every industry, whether it's individuals or teams or companies working together - the best laid plans mean nothing unless the people involved are actually interested in tackling challenges as they come up. Culture eats strategy, and all that. A culture of writing a plan and then either strictly following it or throwing a fit when it can't be followed isn't a culture that can do great work.