Alright, let's get a few things defined from the start that'll be important later:
1. During the DVD years, North America and Japan had different region codes, meaning that Japanese discs would not play on an unmodified North American DVD player, and vice-versa. However, when Sony announced the BluRay format, North America and Japan ended up in the same region, so each's players can play each other's discs.
2. Anime DVDs/BluRays have an absolutely insane pricing and release system in Japan, as Japanese companies are focused on appealing to essentially the "whales" of the anime otaku market. For the sake of an example, I'm going to use Goblin Slayer since it's a relatively new anime that's available on home video right now in Japan and soon in America.
In Japan, this 12 episode series was released in what appears to be three 14,040 yen limited edition BluRay sets, roughly $130.29 each (not including discounts). That's $390.87 for the whole series, presumably. It's hard to tell, even on the translated Amazon Japan.
https://www.amazon.co.jp/s?k=goblin+slayer+blu+ray&ref=nb_sb_noss_2By comparison, Funimation's upcoming Goblin Slayer Limited Edition BluRay box set releasing in October is...$84.98 retail, currently $64.99 discounted.
https://www.amazon.com/gp/product/B07TJKCFPZ/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=13. In the anime boom era of the late 90s -> mid 2000s, it was common for complete North American 24-26 episode anime collections to release as 3-5 episode singles for $25-$30 a disc at around 6-8 discs total. Buying an entire series would cost you around $150 - $240.
This release structure (among other things) led to the collapse of the North American anime market in the mid-2000s.
Nowadays, as you can see the current trend is to release 12-13 episode BluRay sets at $50-$80 a pop. This is what is currently sustainable in the NA market.
Bear this price discrepancy in mind. I'll break the rest of the explanation into a separate post.