I have read enough about Saudi Arabia so I am just qualified to answer this.

It didn't had economic sources and depended on dates and mainly camel products for economic help.

It was underdeveloped and most lived in extreme poor conditions.

Many died due to starvation.

In all quite opposite than today's based on development.

Oil in all changed it's fate.

Source: https://www.quora.com/How-was-life-i...-oil-was-found

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