The same thing happened in HS. Grades were so inflated that it would be hard to detect extremely good students from diligent ones. The SATs were adjusted twice over the years (@ucbalumnus knows more about this than I) so that there was compression at the top of both grades and SAT scores. This meant that admissions committees had to look for more indications of particular strength than were available from GPAs/SATs. It also probably means that the elite schools get a bunch of very diligent but not exceptional students because they can’t distinguish them from the intellectually superior ones.
That clearly is happening now in college GPAs. Have the GREs and LSATs or equivalent also been adjusted to make it easier to get high scores and make it harder to discriminate between the good, the very good and the excellent?
My experience in school but especially watching my kids was that most schools do not actually teach writing proactively but seem to teach it by osmosis. You read a book, write a paper, get a grade, get back a marked up copy of the paper but probably have had to move on to the next book before you can take in much from the markup. Somehow, you were supposed to just figure out how to write from courses like this. ShawD attended a very good private HS where one of the teachers went into detail on how to write a good essay. That course was a full year, if I recall. ShawSon went to a very good public HS where they didn’t teach writing at all (which was a problem because he is both incredibly gifted and severely dyslexic). I ended up teaching him how to write. I learned how to write not in public school nor in an Ivy undergrad but in grad school, when one of my PhD thesis advisors ripped apart the first chapter or two chapters of my thesis repeatedly until I wrote the way he did (which was very good).
Unlike the essentially passive teaching of writing, teachers to try to teach math. There is the kind of utilitarian math, starting with algebra and geometry, that is critical for engineers. Then there is the really logical and more theoretical side of math, where one learns to reason from premises to conclusions in a structured way. In some sense, that is taught in HS geometry (if taught right), in classes after calculus, and in number theory.
Whether math or writing is harder to learn is both student dependent and culture dependent. I think American society has for years told girls they aren’t good at math (or that it is boring or something they shouldn’t be working on). I know a very highly selective graduate program in data science/computational and mathematical engineering. One year, it had fourteen males and two females. But, there was a much less difficult MS in statistics that students could get into or drop down from the more selective program (and I think both of the females dropped to the less selective program). The less selective program (still hard to get into) was 50/50 male/female. The males were geographically distributed. But of the females all but one (a Hungarian woman), the female half was all Asian. About half were from mainland China or Korea and the other half were Chinese-American, Korean-American and maybe a couple of Asian-American ethnicities. That program, while significantly less difficult, would still enable its graduates to enter fairly highly paid jobs. Somehow, young Caucasian women were either not applying or not getting in (I’d guess the former more than the latter) while Asian families were telling their daughters, you can do this.