* students in mostly AP classes who were college bound
* students in no AP classes who were mostly not college bound, or were at least limited to community colleges and state schools (Which are great choices! But often have lower success rates and career outcomes)
For the AP students grades were a joke because all the teachers would happily give out extra credit to any student who wanted it, all in the name of college admissions.
For everyone else grades were a joke because all the students cared about was passing, and teachers REALLY wanted students to graduate, and would give grade bumps to any student who needed it.
I believe most schools suffer from this sort of grade inflation, to the point that grades are at best useful for loose categorization (i.e. A+ students, A-C students, F students) and thats it. It never was and never will be a true meritocracy at scale.