Absolute hogwash. In my parents day (in the 60s) high school included mastery of at least one foreign language and one dead language. Mom and dad read Beowulf in high school, in Anglo Saxon; something modern English majors don't do. And my parents were working class people at working class schools in a factory town. Moving the goalposts to allow morons to get a high school diploma isn't improving educational attainment. Hell, I could point out a dozen examples of decline in Bachelors degrees in my lifetime.
This was a meme a few years ago: a 1800s era Harvard entrance exam, and Harvard was the easy school: https://graphics8.nytimes.com/packages/pdf/education/harvard...