The Saudis love American-built mega projects for many reasons.
American engineers finish their work before schedule, with top-of-the-line quality, and the American companies were able to help Saudi society in many ways.
Not only did they build the necessary infrastructure for oil production and exportation, but they also built many useful societal structures for local Saudis, like roads, hospitals, schools, and sports facilities, enabling Saudi employees to own homes. This was something unique at the time and not seen anywhere else in the world. Only in Saudi Arabia could a company employ you, provide the best health care, and help you own a home. And we are not talking about a two-bedroom home; we are talking about an eight-bedroom home or larger.
The most important positive impact on Saudi society, however, was the training of Saudis. After many years, other companies from different countries came to Saudi Arabia, and local Saudi citizens gained very little from them. For example, Japanese companies ran mega oil projects in northeast Saudi Arabia, but the type of development in that area didn't benefit any of the local Saudis. These days, Chinese companies receive billion dollar contracts, but are slow to finish jobs and do not contribute to the Saudi job market in any way.