Niaz,
I understand the idea behind Saudi Vision 2030; the Saudis want to diversify and export finished products, such that 50% of exports are non-oil based. While the plan is good (and they should do this to some extent), it doesn't take into account the more economical method of investing in other countries so that you can maximize profits. Many smaller projects throughout the world rather than one big city like NEOM, where a lot of the work will be infrastructure building.
I would say, they should look at the Japanese model of investing abroad, such as in the textile industry in Bangladesh. Japanese investors bring capital, know-how, and contracts to sell to other countries, and sell around the world. The Japanese workers are the top talent managers and middle management supply chain experts.
Hundreds of Saudi SEZ throughout the world, would earn them more than one big city where they will have to bring in labor and ship in raw materials. It would be more profitable to bring their investments to these countries, and in turn modernize these countries through trade, increasing the demand for Saudi oil, and creating a virtuous cycle where Saudi has more customers for their oil.
These nations would then have the development and funds to protect Saudi Arabia, not only because of their dependence on Saudi Oil, but because of their trade ties.
(p.s. you linked to your computer)
the saudi strategy is sound. it has two drawbacks - 1. it does not employ saudi labor
2. no one has managed investments in perpetuity making money. sooner or later you make mistakes and money is lost