During the period of primitive history, many wild animals lived on Earth, which ancient people could feed on

During the period of primitive history, many wild animals lived on Earth, which ancient people could feed on. however, they often went hungry. how do you explain the reasons for the frequent lack of food in ancient people?

The ancients were not engaged in farming, did not raise livestock and did not cultivate the fields. In this connection, they could feed on gathering or hunting. Naturally, it took time and skill to catch or kill a wild animal. Often there were such cases when there were no wild animals or it was not possible to catch, or people themselves became the prey of a wild animal.