The main reasons Jamestown was unsuccessful in the first five years were:

• Disease and Illness: The swampy location caused waterborne diseases such as dysentery, malaria, and typhoid. These diseases took a heavy toll on the settlers, with high mortality rates especially during the first year and the "Starving Time" winter of 1609-1610.
• Lack of Skilled Labor and Agricultural Knowledge: Many early settlers were sons of English gentry or craftsmen who did not want to do manual labor or farm. This led to food shortages and inability to sustain the colony.
• Focus on Quick Profits and Gold: The colonists were overly focused on finding gold and quick wealth like the Spanish had, rather than establishing a stable economic base through farming or trade.
• Poor Location and Environmental Challenges: Jamestown was located on a marshy island with poor hunting prospects and bad water sources, contributing to disease and food scarcity.
• Hostile Relations with Native Americans: Conflicts and warfare with the Powhatan confederacy cut off trade and food supplies from native sources, making survival harder.
• Internal Leadership and Resource Problems: Initial governance issues, lack of effective defense, and repeated supply difficulties compounded challenges in survival and growth.

Overall, a combination of disease, poor planning, insufficient labor for farming, hostile native relations, and environmental hardships made Jamestown struggle to become profitable and successful in its first five years.