Why Political (In)stability Should Matter to Investors and Economists?

Recent developments in Saudi Arabia highlight the dangers of political instability:

https://www.washingtonpost.com/world/saudi-arabia-detains-princes-ministers-and-billionaire-investor-in-extraordinary-purge/2017/11/05/ea0aa25c-c1fc-11e7-af84-d3e2ee4b2af1_story.html

https://www.nytimes.com/2017/11/05/business/saudi-prince-alwaleed-investor.html

US-Saudi Connection:

https://www.nytimes.com/2017/11/04/world/middleeast/saudi-arabia-waleed-bin-talal.html
Saudi Crown Prince - Autocratic Tendencies
https://www.washingtonpost.com/news/global-opinions/wp/2017/11/05/saudi-arabias-crown-prince-is-acting-like-putin/

Related:

Inside Saudi Aramco's Kingdom of Oil

http://fortune.com/2017/10/24/saudi-arabia-aramco-oil/
https://www.bloomberg.com/news/articles/2017-11-05/saudi-prince-s-corruption-sweep-reaches-aramco-board-council