We get details from within the story that suggest that the original ceremony had a lot more "ceremony" than it does in the present day of the story. For example, the black box used to be kept in a carefully kept state and it looked more official. Now the box is not maintained, it looks a little beat up, and it is stored, almost absent-mindedly on the top shelf of a local store. In the past there were official wooden pieces to represent each family. Now the town just uses slips of paper that are easily thrown away at the end of each year's lottery. It states in the story that the original ceremony was a much longer and drawn-out all day affair, it was probably a lot more formal. Now it seems as if they are trying to just "get it done" with very little "pomp and circumstance." The reason for all these changes suggests that the ceremony means less now than it did then, but there is still a significant reluctance to end the process of the lottery like other towns have. There is enough of the original tradition in place for the people to still think there is a need for this yearly ritual and sacrifice.
Because Mr. Summers is presented in jeans and a white shirt and I know a little about the author, I place this story in my brain about early to mid 1900s. It seems by the intermittent comments of Old Man Warner that he has experienced the lottery as far as he can remember. He is presented as in his 70s.
This edict "lottery in June, corn be heavy soon" demonstrates that this likely began when people felt like a human sacrifice to the gods or to God was necessary to receive the blessing of a good corn crop. This could have been a Puritan or Pilgrim era idea.
Obviously by the early 1900s farmers began to know through science a thing or two about watering and fertilization. So, it is a wonder that the group hadn't yet realized that their idea about their crop had come and gone.