Why did Portugal have difficulty fully controlling the Indian Ocean?

Portugal never fully controlled the Indian Ocean due to several critical limitations in their maritime and colonial strategy:

• Lack of Naval Resources: Portugal lacked the sufficient number of warships required to effectively police and control such a vast expanse of water.1
• Failure to Secure Strategic Chokepoints: While they captured key locations like Goa, Malacca, and Hormuz, they failed to capture Aden at the entrance to the Red Sea. This allowed traditional trade routes through Egypt to persist, undermining their attempt to monopolize the spice trade.1
• Manpower Shortages: With a home population of fewer than one million people and commitments across Africa and South America, Portugal was desperately short of the manpower needed to maintain a true land empire or fully secure their maritime network.2
• Dependence on Local Traders: The Portuguese found it impossible to manage the local trade networks without the assistance of Arab and Hindu merchants, whom they had initially intended to oust.1
• Internal Corruption: The intended royal monopoly on trade was frequently undermined by Portuguese officials and soldiers who engaged in private trade to line their own pockets.12