The deeper reality is that Saudi Arabia have provided (or occasionally withheld) stability to global oil markets since the early 1970s.

KSA are the world's reserve capacity supplier of oil. Given that world transacts globally and is a highly liquid commodity (in the economic sense), *even where KSA don't directly provide the US with much of its oil, the Kingdom's management of production and leadership in OPEC have a profound impact on global oil and through it, global economic and strategic stability.

There are countries with larger total oil reserves, more exports, and greater production (Venezuela, Russia, and the United States, respectively). Saudi Arabia's strengths are the quality of its oil ("light sweet crude", as contrasted with heavy sour crude from Venezuela, which requires light volatiles simply to extract it from the ground, hence periodic headlines about the US "selling oil to Venezuela", which is more misleading than informative), and the low cost of extraction. Additionally, Saudi Arabia have excess capacity --- their pumps are not running full out --- which means that by increasing or decreasing their supply, they can effectively set global oil prices. (Again: liquid assets, it's possible to move $100 of oil by tanker for about $1 in fuel, making arbitrage and cross-supply highly viable, unlike far less readily handled fuels including coal and natural gas, both of which require special handling.)