The essay is very light on evidence. Pathological cases (such as buying grades) aside, maybe grades have generally increased because teaching has gotten better? I certainly wouldn’t posit this as an absolute truth but research into teaching methods has gotten better. 50 years ago teaching wasn’t the least bit scientific. Modern research into teaching methods is a proper science, even if it’s hindered by many false starts and slow adoption. Modern technology also offers vast potential for better teaching and learning.

I’m not sure how useful grades are when everybody gets an A. But if the reason is a phenomenal teacher (and better teachers reproducibly produce better performing students [e.g. 1]) then maybe grades are simply an unhelpful metric. “Stopping grade inflation” isn’t just not a solution, but actively counter-productive. “Grading on a curve” when every student has mastered the curriculum (which, in higher education, is entirely achievable) is bogus.

[1] https://onlinelibrary.wiley.com/doi/full/10.1002/jae.2539