Curving policy and competitive nature of the student body impact far more than just premed classes. A high GPA is necessary coming out of undergrad for many jobs and grad programs.
Gradeinflation .com hasn’t been updated since early 2016, some areas of the site even have older data that that…so that should not be considered a valid source of info.
Average grades can and do change over 4-6 years, as evidenced by what has happened at Davidson average gpa in that timeframe. https://www.davidson.edu/offices-and-services/registrar/graduating-class-profiles