This anime for Sumou can be seen as its last hope. They have tried almost everything bar an anime in trying to raise its sales, even a little bit. They gave it a crossover with Kuroko, had Kubo praise it on a wraparound, had it be advertised at sumo matches, etc. It didn't get TV promotions but you can say that's because it didn't catch on enough to do so. It must have done, and still is doing extraordinarily well, in questionnaire results to keep around despite not breaking 50k in the Top 50.
Dr. Stone, if it continues in this trend will be Sumou 2.0. Its getting reprints so we'll have to see how far that will go next volume but if I recall correctly, it had reprints last volume and it still didn't do particularly well. Right now, both Stone and Bokuben are losing to Kenja no Mago, a reincarnation story light novel which started in Narou and is serialized in Kadokawa's Young Ace Up, an free online manga magazine which has a fraction of Jump's influence. Stone and Bokuben might have longer legs but that doesn't mean they didn't start lower. I understand that Stone is ripe for an anime, a daytime anime. But to get that, the producers, not just Shueisha, have to see that their investment will be rewarded as daytime anime cost significantly more than late-night anime. I'd like to think the minimum for that is that its able to break 100k in the first week. Obviously this is an arbitrary line and not entirely accurate but most manga that got daytime anime have done so.
Even if HZ doesn't boost the manga sales by much, it will have still received an anime, which is a huge achievement if you have a manga in WSJ. And if the manga finishes at around 20 something volumes, that's an amazing run for WSJ and on top of that the anime will cover 17 volumes and a crucial part of the story.
I don't see the point of bringing up stuff like Kenja no Mago, since WSJ mostly care about their own properties and they'll do their best to stay relevant as the biggest manga magazine by focusing on their own properties and that Kenja manga definitely came to life in a different way from what you would see in traditional magazines, that has a different demographic for sure, LN fans. How many other hit manga do Young Ace Up have, in comparison to WSJ?
WSJ manga don't seem to have many problems when it comes to getting anime adaptations, I can't be the only one that has noticed this, it looks like producers and studios will easily jump in on the chance to work with such a large publisher and magazine. If a manga in WSJ lives for 2-3 years or longer, then it's almost guaranteed to get an anime at some point, looking at recent trends.
Your minimum might have to change since I can't be the only one that can see that print sales are going down overall? I'm sure that WSJ manga do well in digital sales, but we'll never know, since those stats don't get released.
Edit: Dr. Stone doesn't necessarily need a daytime anime, but it's likely that's where it would end up. But considering the educational aspect of the manga, I could totally see NHK funding a season or two, for their educational channel, why not, right? The possibilities are endless.
Edit: And regarding Bokuben, it's the shounen romcom that is growing the most right now. Yuuna which is also from WSJ is also quite big and new, but what else is there when it comes to new shounen romance series, especially from the three big shounen manga magazines? Magazine from Kodansha have hit the jackpot with Kanojo, Okarishimasu and Go-Toubun no Hanayome , they're both doing quite well, but they're still behind Bokuben, they both have huge growth potential, but they're probably going to always be slightly behind Bokuben since Bokuben has more exposure.