Because while Black Clover has also decreased, the overall percentage of sales it has lost volume over volume has been very small. Food Wars on the other hand was barely selling like 50% of its peak by the time it ended. That, and the actual reception of it plummeted.
Also, Shueisha has also said they will cancel a manga even if it's successful if it begins to feel stale having it around. So all those things probably didn't help Food Wars.
Shokugeki's VoV decline was not dissimilar from BC's at all, it feels like this conversation keeps happening and always goes the same way. It had small but consistent VoV declines that only started getting really visible towards the end, and even at the very end it was still selling more than BC does now.
BC's last volume sold 163,489 copies which is 62533 copies less than its volume 15 had sold on week 3 (
27,7% drop), now if you checked how much soma lost over the same timeframe you'd get that it lost 112991 (
25% drop), hell I'll throw in Toriko as well (
23,8% drop), ironically out of the three the one with the biggest decline relative to its peak is BC lol. I don't get what the point of pretending BC isn't on the exact same trajectory as series like Soma or Toriko is, it's the exact same trajectory except its starting peak is lower than both.
I can't believe we're more than 5 years in and still have people here insisting Black Clover is some unpopular flop.
It's done 5 years already, it can do 5 more.
Nobody called Black Clover an unpopular flop and not to burst your bubble but Soma certainly wasn't either, this habit of treating any talk around BC's decline as if it was hating on the series is ridicolous and not healthy for discussion. The fact that you already see people say "I won't comment on the matter because of how defensive people get over it" is very telling.
No, Black Clover isn't a flop, yes, it's declining, and yes, this trajectory is no different or smaller than what we've seen in the past.