The Persian Gulf, a large bay extending northwest from the Arabian Sea into the Asian continent, covers an area of approximately 240,000 square kilometers and is bordered by numerous countries. This region is exceptionally rich in petroleum resources, holding about half of the world's oil reserves, and is often referred to as the world's energy treasure house. Among the Gulf's coastal states are major oil producers such as Saudi Arabia and Iran. While both nations possess substantial oil wealth, there is a significant disparity in their per capita GDP. Iran's per capita GDP is around $4,800, whereas Saudi Arabia's reaches a much higher $30,700. This raises the question: why is Iran less affluent than Saudi Arabia despite their shared oil abundance?

First, Saudi Arabia benefits from greater resource wealth per person. The Kingdom of Saudi Arabia, located on the Arabian Peninsula in West Asia, spans 2.25 million square kilometers and has a population of approximately 35 million. Historically a underdeveloped agrarian and pastoral society with widespread poverty, Saudi Arabia's fortunes changed in the 1930s with the discovery of vast oil reserves. To counter British influence, Saudi Arabia aligned itself with the United States. In 1933, it leased a 932,000-square-kilometer oil concession to an American oil company for 66 years. Subsequent large-scale exploration, also conducted by Americans, led to the discovery of significant oil deposits in Saudi Arabia's Al-Hasa region by 1938. This transformation turned the nation from a backward agricultural state into a major oil exporter. Today, Saudi Arabia's proven oil reserves stand at 297.6 billion barrels, accounting for about 17% of the global total and ranking second worldwide. Additionally, the country possesses substantial natural gas reserves of 9.4 trillion cubic meters, representing 4.6% of the world's supply and ranking sixth globally.

The Islamic Republic of Iran, situated on the Iranian Plateau in West Asia, covers about 1.64 million square kilometers and has a population of roughly 88.55 million. Iran boasts a illustrious history, with the Persian Empire once spanning three continents. However, in modern times, it suffered from foreign invasion and became a semi-colonial, semi-feudal society, evolving into a落后的 agrarian nation. In 1921, Reza Shah overthrew the Qajar dynasty and established the Pahlavi dynasty. Following Saudi Arabia's oil discoveries in the 1930s, Iran also embarked on extensive petroleum exploration, identifying several large oil fields. The Pahlavi regime forged close ties with the United States, leasing the exploitation rights of multiple major oil fields to American companies. Consequently, Iran also transitioned from an agricultural economy to an oil exporter. Presently, Iran's proven oil reserves amount to 155.6 billion barrels, constituting 9% of the world's total and ranking fourth globally. Its proven natural gas reserves are 33.5 trillion cubic meters, representing 17% of the global supply and ranking second worldwide. Thus, while Iran's oil resources are less abundant than Saudi Arabia's, its natural gas reserves are more substantial. However, with a significantly larger population, Saudi Arabia enjoys a higher level of resource wealth per capita.

Second, Iran has been subjected to US sanctions. Initially, both Saudi Arabia and Iran established close relations with the United States and leased extensive oil concessions to American firms. However, following the 1979 Islamic Revolution, which overthrew the Pahlavi dynasty and established the Islamic Republic, Iran's relationship with the US deteriorated sharply. Iran's Supreme Leader at the time, Ayatollah Khomeini, declared that the country's oil belonged to God, not to Wall Street, leading to the nationalization of oil assets previously controlled by US companies. The ensuing deterioration in US-Iran relations resulted in prolonged economic sanctions against Iran. These sanctions have hindered Iran's industrial upgrading and contributed to its economic decline. In contrast, Saudi Arabia has maintained strong ties with the United States, permitting the establishment of US military bases on its soil and regularly purchasing American weapons, effectively solidifying its alliance. The substantial revenues from oil exports have enabled Saudi Arabia to invest in developing basic and modern industries, aiming to reduce its economic dependence on oil and pursue industrial upgrading and economic diversification. As an industrial powerhouse, the United States has supported Saudi Arabia's industrial development, further contributing to its more diversified economy.

Considering these factors collectively, Saudi Arabia has achieved a higher level of prosperity compared to Iran.