There were several factors that contributed to the transition from using indentured servants to using enslaved Africans as the primary source of labor in English colonies in the Americas:
1. Cost: The price of indentured servants increased as the supply of workers decreased. By contrast, the transatlantic slave trade made it possible for plantation owners to purchase large numbers of enslaved Africans at relatively low prices.
2. Supply: As the population of European indentured servants declined due to improved economic conditions in Europe and better working conditions in the colonies, plantation owners turned to the transatlantic slave trade to meet their labor needs.
3. Chattel slavery: The legal system in the English colonies began to recognize the concept of chattel slavery, which treated enslaved people as property that could be bought and sold. This made it easier for plantation owners to justify the use of enslaved Africans as a permanent source of labor.
4. Racism: As the number of enslaved Africans in the colonies increased, racial attitudes began to shift. White colonists began to view Africans as an inferior race and saw slavery as a way to maintain control over the African population.
Overall, the transition from indentured servitude to slavery in the English colonies was driven by a combination of economic, social, and legal factors, as well as the racist attitudes of the time.