They all look like either visual novels made with Ren'Py or SNES style console games made with RPG Maker. Do they have amazing writing? Why are they so expensive?

TL;DR: They want to pretend to be a premium label/boutique thing without actually putting in the effort.

More cynically: They want their buck for their bang, so any sale is one that helps them make back dev cost and they know it's niche since you can just look up pictures for free on the internet.

Japanese games have always been overpriced. They also do not consider outside sales to be of any interest to them. In fact, most Japanese people in business rarely consider outside sales of any consequence. Normally, gaijin are the ones pushing them to sell out side Japan.

Do not expect any price drop until xmas....assuming they drop much at all.

Because thirsty Otaku pay premium buckaroos...

Tariffs, taxes and low number of sales.

I'm going to hazard a guess and assume it's because they are niche titles with low demand, so to cover whatever production costs they have and whatever GOG asks for they have to increase the price to make a profit.

If their intended audience is willing to pay for it then there's probably no incentive to lower costs too.
If people are willing to pay 10 dollars for a product, why would you cut the price to 5? Price cuts happen when there's a competitor offering a better deal.

I'm probably super wrong though, I really don't know.

I would be happy to pay the high price occasionally for an incredible niche game like Disco Elysium or Flashback, but these seem expensive and low quality. What is the appeal?

It's because every digital bit of Japanese games is handcrafted by a grand-master from the raw resources of holy Mt Fuji.

Anime boobs, apparently.

What also tends to really surprise people is that contrary to what they see in anime, manga, and videogames, Japanese people deep down loathe all foreigners.

Japanese culture does not at all tolerate those who are different or who "cause trouble for others" and as such, does not want anyone there who disturbs their "social harmony".

[url=https://en.wikipedia.org/wiki/Wa_(Japanese_culture]https://en.wikipedia.org/wiki/Wa_(Japanese_culture[/url])

But anime boobs are everywhere. I saw some on a t-shirt the other day. Hentai is way more impressive creatively. These games just look boring.

Maybe because the japanese have higher prices at home. This involves anime, manga and games are expensive more than in any other country and they usualy pay more in Japan then the rest.

because they're there to empty the wallets of porn addicts, do nofap and you'll have no need for such sinful games

I wouldn't even consider them porn, though. Those 3D modeled sex games on GOG are clearly intended as porn (although they look boring as well), but these waifu games could be like erotic fiction and tastefully crafted. They don't seem to be super explicit, but I'm not paying these prices to have to play through some RPG Maker levels just to see a handful of fancy illustrations in the cutscenes and assess the writing. I'd rather buy a light novel I can read half of in the store.

That wouldn't surprise me. They have a pretty large and reasonably affluent internal market. They have about 1/3 the population of the US and are pretty well off.

Even in their large urban centers, there doesn't seem to be a lot of pressure to learn English and most people don't (some people who are likely to interact with tourists as part of their work will speak little to medium amounts of English, but that's it).

If I compare that to my own francophone province where we are about 8 millions, most people in Montreal (our main metropolis) speak at least working English and content creators here tend to be very interested in exporting their work to international anglophone markets (because unless you are wildly successful, you'll make relatively lean living on a 8 million people market and you might be somewhat better off if you manage to make inroads across the sea to the 68 millions people living in France, but that is far from a guarantee... a lot of artists don't).

I didn't get that impression. People I encounter in Japan tend to be pretty polite and helpful. Some are even friendly.

And not only am I a tall bulky non-Japanese who doesn't really speak the language, but I also don't really follow Japanese fashion (for starters, I have a full mustache and beard and I cut my hair pretty infrequently so they tend to be on the long side). In a crowd in Japan, I stick out.

Some people are cold (probably a mix of my different appearance and my not speaking the language well), but there are people like that everywhere and at least there, they are polite enough just to be cold to you and not scream at you to learn their language or go home (something I have seen in North America, though thankfully, infrequently).