The article mixes up the plans to diversify from oil production with all the talk about helping the worse-off. These are two separate issues, and changing one won't magically help the other.

Right now, Saudi has a huge income from oil. If they divest well, they could have a huge income from investments. In either case, the lot of the poor in Saudi Arabia doesn't change. Unless they change how they allocate the money, the rich will get richer and the poor will get poorer.