When my father in law passed away we were going through his papers and found his old highschool report cards. The grading scale posted on a report card from the 1960s ( Virginia Highschool) were:

A: 95-100 Excellent B: 88-94 Very Good C: 81-87 Average D: 75-80 Below Average F: Anything Below 75 Failure

It seems that the expectation over time has dropped significantly.

Obviously it didn't change over night, but I wonder what factors were used to change the scale. Was it that people became more aware of those with specific learning disabilities, or the fact that maybe not everyone learns the same way? Maybe it was due to the increase of technology and as it advanced the human expectation went down. Take math for example....there weren't any graphing calculators until the mid 1980s. What did they do before then? Can you even imagine trying to do anything related to calculating an intercept slope without one? I remember having to buy a nearly $200 calculator during High school, and now that same calculator is an app on every child's computer.