>Also I don't know where you got your 1750 figure from, but it's likely to be more like 1950 or even later in most countries.
I picked 1750 because that is the earliest date before which I am sure that the people who eat a lot of rice would definitely not have had access to precisely-machined steel parts.
I strongly suspect that precisely-machined steel parts are necessary to turn just-harvested rice plants into brown rice: older rice-processing methods can only produce white rice (more precisely, rice with at least 90% or 95% of the bran removed whereas modern brown rice has most of the bran intact).
(Precisely-machined parts as also needed, I suspect, to produce rice with no bran at all attached -- 100%-white rice we might call it -- where most of the grains are not broken into pieces.)
Both of the creators of the 2 Youtube videos I linked to say that when they were children, their families of origin used the technique depicted in the videos to get the rice they needed to survive. The technique makes white rice and cannot be modified to make brown rice: one of the creators outright says that the process of removing the husk also removes the bran. If there is some other technique that does not rely on post-1750 technology that can make brown rice (husk removed, but bran left on the grain), why weren't subsistence rice farmers using it? Either it does not exist (my guess) or the rice farmers prefer white rice to brown rice.
I know that many internet commentators say that traditional subsistence rice farmers since the dawn of rice culture ate brown rice. But lots of falsehoods get repeated over and over on the internet.