Online manga sales made up more than half of overall market. Rakuten is not the only platform providing the service (Kobo, their platform, is a good one and I'm a returning customers there). Nonetheless, their figures can be treated as a good proxy metrics when it comes to online market for manga. I personally take it with a grain of salt.
It's known that manga sales are trending up since the past couple of years. Last year was even higher despite (or rather, thanks to) pandemic. https://www.animenew...in-2020/.169987
As for Naruto / Boruto franchise, it's a gone case since the disastrous ending. Not surprised that in the rank it's part of the long tail, 74 and 88 respectively. A manga that ended 7 years ago performing "better" than its successor by 14 spots. Yikes.
If only they didn't mess up with NH & SS ending that jeopardized the whole story structure, it would've been in top 10, or at least top 20.
One Piece is in the top 10. Likewise MHA. Heck, even Bleach that suffered from declining sales in its last 1/3 of volumes is at rank 48.
Not only Boruto is performing worst than Naruto, a manga that ended 7 years ago. Its sales volume by volume today is gradually declining. To put it into perspective, those who dropped the manga in volume 15 are Boruto/Naruto loyal readers that has been waiting for 7 years, hoping the manga would be better. That shows even the pro-enders have given up on Naruto.
Made no mistake, I believe heads were rolling. Not just the recent editor who got fired. Why would they need to move the manga to a second tier distribution? Ever wondered why suddenly Hinata / NH / SS never been seriously featured in Boruto manga or anime? Why Sakura got the top 1 most popular character in Boruto poll? Why the story of the franchise move very slow and gets all over the place?
The franchise lost over 90% of its paying customers. Of course they'd be scrambling around to bounce back.
Well, there goes me hoping to finally get Blue to give his own thought instead of just providing a link and making us come up with the answer.
Wait they recently fired another editor? Just to double check, you don't mean kodaichi who was the writer replace last year right? They actually recently fired someone else who was the editors?
As for why the story is so slow, here's what I think. If Kodaich was telling the truth and he was hired to only write 13 volume. Just to remind people companies don't like hiring people now a days because when they are fired they can sue, so instead they just use contracts, and when they want you gone; they just don't renew your contract. Then it means if we say it was originally for 13 instead of for every volume, they wanted at least 26 volumes of this manga to take about 10-15 years to write. They wanted another round of Naruto hopefully making the same amount of profits. The thing is Naruto actually had a goal and some plots that were able to keep people invested. Boruto completed his goal in the movie and doesn't have many plots.
So, what they did is they introduces a copy of the longest running plot in Naruto the chase after Sasuke, and hope they can make it last for 15 years. As well as going as slow as possible using build up as an excuse. Of course, since everyone has already seen it and they are going so slow; they are losing readers instead.