We've all seen lists of the greatest players or top coaches in football history, and almost all suffer from recency bias. The greatest player lists have few athletes who played before 1960, and while lists of top coaches typically stretch back further, they are less likely to include someone who influenced a once-popular aspect of the game that has since died out.
The flip side of that effect is evident in a list published by Walter Camp in January 1912 after being asked to identify the 20 individuals with the greatest impact on football. I estimate that the average fan might recognize only three or four of Camp's top 20, while even knowledgeable students of football history will not recognize a few. Of course, Camp' stop 20 is a time capsule because he prepared his list before football fields had end zone, and the forward pass was in its infancy. Moreover, Camp was a player and coach, but his primary contributions came as an administrator. He helped organize the game and establish its rules on the field and off (e.g., eligibility standards). So, it is unsurprising that many of his top 20 played similar roles.