[a-priori]

That's not how it happened at all. The Kingdom of Saudi Arabia, as a unified state, can be traced to the Treaty of Darin of 1915 between the United Kingdom and Abdul-Aziz Al Saud (aka 'Ibn Saud'). In the treaty, the UK agreed to protect the sovereignty of the House of Saud, and in return Ibn Saud agreed not to attack British protectorates in the Middle East and to support Britain against the Ottoman Empire.

This treaty (and the subsequent Treaty of Jeddah in 1927) legitimized their control over their territory and allowed Ibn Saud to go on to create the Kingdom of Saudi Arabia in 1932.

The Arab people had no part in the creation of the Saudi state. It was created by conquest combined with the support of foreign powers (the United Kingdom).

https://en.wikipedia.org/wiki/Ibn_Saud https://en.wikipedia.org/wiki/Treaty_of_Darin