A bunch of reasons: key decision makers being pretty far removed from the day-to-day of projects; everyone lying about how poorly the project is going to CYA; p

A bunch of reasons: key decision makers being pretty far removed from the day-to-day of projects; everyone lying about how poorly the project is going to CYA; project timelines being so long that these projects end up losing visibility in the C-suite long before completion; etc. In some cases, like Hertz, they do actually damage their partners. But most of their clients are massive multinational conglomerates who can readily suffer from a string of failed multi-million dollar projects. Like any parasite, they know not to kill their host.