The public school has dumbed down the curriculum over the last 50 years to reach some equity with those who are very slow, or just don't give a damn, but mostly, it makes it easier for schools to maintain a high success rating to get a bigger piece of the tax payer pie.
Public education will be little more than tax payer funded daycare with a focus on indoctrination and in some areas, it already is.
I have blood tests every 3 months which includes my Vit D. My amount of 1000 units works for me, but individual needs are of course different. 5k -9k units sound very high compared to others I have talked to, but if your blood tests demand that intake to stay within normal parameters, then you take that recommended intake. I wouldn't recommend those high dosages to others without checking with their medical professionals.
I take Vitamin 3D 1000 units everyday (Vit D is inexpensive). Sun helps, but if you use strong sunscreen, that can interfere with Vit D synthesis, which maybe a contributing reason why so many folks are found Vit D deficient.
Don't underestimate the work of NGOs that are funded by the likes of Soros. They are also ponying up the money for these illegals to pay off the coyotes/cartels.