Haha nah. Yeah, no extended hiatus, but it does make the pacing for wano come out differently.
I constantly see the western fanbase complain about it. I don't know how the local fanbase reacts, but breaks haven't really been normalized in Jump.
Western fanbases are whiny. A lot of current readers get into a series after having watched the anime for a bit. So they automatically start comparing the pacing of one series to the anime and to another manga that they know which has "better pacing".
What they probably wouldn't realize is that the pacing of that particular series has remained consistent throughout in the manga for years.
Same reason people liked to complain about a series using big panels and not progressing the story too much per chapter or like how Bleach fans whined incredibly about the fact that Kubo usually used the first two pages as a sort of recap of how the previous chapter ended.
Its like how reddit works. If whining about something is the trend, people will just nod their heads and jump in. If praising something is the trend, that's what people will do. Bandwagoning, basically.
I doubt the japanese themselves care much about how much the story progresses and rather about how well its done. Japanese adore Oda and they are well aware of the fact that he got hospitalized and why he has to take breaks.
So if the series is declining in sales, its probably cause the content in Wano Arc just wasn't good enough.
Also, man, Jump is really banking on dark series with demons lately.
Kimetsu's influence. MHA influenced series to go for the superhero thing. Kimetsu's influence is a lot stronger.
But the demon thing was always popular tho. It never became unpopular in Japan.
