Why Saudi Arabia Is Building a Linear City

So it seems that no 'line' cities have ever worked and now the Crown Prince wants to build one? More like a Vanity project than a Prestige project. With all the space east of the coast, why would anyone want to live further away from where all the jobs will be? I understand why subterranean city levels make sense to build first and how it does create a more human friendly surface level, I don't get the social, economic or ecological sense of a line. Lots of cities have multiple lines spreading from a central hub, but just one? 

The Saudi-Egypt Causeway does make sense and would make overland transportation to Egypt faster. 

What I really feel is that "Neom" could become a new Ras Tanura or Yanbu petroleum shipping port. Bypassing the Persian Gulf and Iran and cutting down shipping times to Europe and North America.

Eventhough Egypt is not an OPEC member, if Egypt's own oil production slows or Iran becomes openly hostile to any oil going through the Persian Gulf, oil and gas pipelines from Saudi Arabia to "Neom" across Tiran Straight to Port Said to connect to Arab Gas Pipeline for gas and to Suez to Ain Sokhna to connect to Sumed Pipeline to Sidi Krir for oil could be beneficial Egypt and Saudi Arabia come to a deal. An alternative gas pipeline to Egypt via "Neom" also gives Syria, Lebanon and Jordan an option should Israel sabotage the link they have that passes just south of it. 

I believe that the money the Saudis are wasting in this could be better spent ending their subsidizing of petroleum and building a renewable energy system. In a country which is entirely classified as a hot desert climate and where less than 7% of its area is suitable for cultivation, that leaves a lot available for solar and wind. Once they get off their own oil, then they could turn around what they once subsidized to their own people and sell that at the market rate and make $80 billion a year or not and hoard it.