Final answer:
Benjamin Franklin retired from his successful printing business to concentrate on his scientific and philanthropic interests, letting his family run the business so he could devote his time to public service and intellectual pursuits.
Step-by-step explanation:
Benjamin Franklin was a multitalented individual with contributions spanning numerous fields like printing, science, politics, and diplomacy. His career as a printer helped to establish him as a wealthy and respected individual within the colonies. The retirement from his printing business in 1748 was a decision motivated by a desire to dedicate more of his time to scientific inquiries and public service. His involvement in various philanthropic projects was guided by his deist beliefs, which emphasized personal morality and the pursuit of knowledge through activities such as founding the American Philosophical Society and contributing to the establishment of the University of Pennsylvania and Pennsylvania Hospital. Therefore, the decision to let his family run the printing business stemmed from his wealth, respect, and shift in focus towards public service and scientific endeavors.