why is japan not buying it more?

Maybe not everyone likes comedy and is looking for more serious titles. Maybe not enough ads. The main plot (romance and ball hunt) is a stretch with subplots that lead almost nowhere. Also it's Jump+ title, they are selling less (SxF and maybe Kaiju are exceptions). It's really hard to say about any specific reason. Dandadan is crowd pleaser but somehow remained overlooked

@Chevesus i googled more and volume 1 of dandadan actually sold 200k copies so thats a lot almost same high as spy x family and kaiju 8 but it failed to maintain the sales in succeeding volumes heck there still no anime boost still especially there is no japan reprints for the volumes yet so ye its a mystery why this series is being overlook there

there definitely has been an anime boost its nearly up to selling 200k copies per week

It seems that some people think Dandadan is not worth reading, so opinions are divided. I don't read the manga, but I like the anime.
https://translate.kagi.com/Japanese/English/https://aritai.jp/dandadan-uninteresting-termination/
https://translate.kagi.com/Japanese/English/http://yaraon-blog.com/archives/266287

The series was #3 in the monthly Oricon charts for October with 560,000 sales, only beat out by One Piece and Jujutsu Kaisen. It was the best selling currently airing series for that month and will probably at least hold or may even go up this month with increased word of mouth, plus yesterday's episode has been trending on Japanese twitter for a whole day. It should also be noted that even with those 560,000 sales the entire series was free to read on Jump Plus for the month of October. So yeah its sales are not on the level of Demon Slayer or JJK, at least yet, but we don't have to concoct some bullshit narrative about it not selling, because it is.

Uhh, do you know, before a manga turn into anime, 4 million copies sell is a lot already?
Do you know even Jujutsu Kaisen only has 8 million copies sold prior to season 1 , and it's on Jump instead of Jump+

Dandandan seems to lack from what I've heard online (correct me if I'm wrong), an overarching goal ie op villain. Every shonen series has one so hype is hard to sustain. It doesn't cater to obsessed fans such as yuri and yaoi nor the casual family looking for their first manga as its themes are too dark. Its romance is too tepid, considering how well the MCs get along together so even that hype is weak.

I think it is in the unique position of being good, having a mish-mash of genres and themes but lacks both the ability to build hype (no OP enemy to overcome, no great goal, tepid romance) and fails to target the people who buy goods (yuri and yaoi fans, family people looking for their first manga).

@Ventus_S how many volumes for jjk before the anime? dandadan has a lot already with 16 volumes

the sales are mid compared to the hype

@deg Hey maybe make another bs topic just to really hammer home how miserable your are right now that Dandadan is getting universal praise.

@Ventus_S how many volumes for jjk before the anime? dandadan has a lot already with 16 volumes

the sales are mid compared to the hype

@deg You're comparing the appeal of Dandadan to cookie cutter battle/nekketsu shounen for the japanese audience, laughable.