I also think they were half expecting that most of the fans wouldn't stick around after ending, no matter the outcome, so they've made a calculated call with the ending and ran with it. They didn't have to be great mathematicians to figure out that NH + SS were a much bigger and louder base than us.
I disagree though. I'd like to think they are expecting more sales with Boruto series, that's why the publisher dared themselves to make extreme turns (kill NS, establish NH+SS, capture the new audience based on NH+SS).
If you recalled, a few months before the manga ended, there was a poster drawn by Kishi to promote the so-called "New Era" project. Anyone remember?
Most likely by then the decision of the story has already been long established. I wouldn't be surprised that by the time that poster appeared, The Last and Boruto the movie has already in pre-production (I'm quite sure Boruto The Movie is already completed when The Last aired, since the end of The Last, we had a promotion of Boruto Movie "coming soon"). Not to mention other media, such as games, which takes a lot of time to produce.
I've discussed a lot about the principle of vital few (http://www.narusaku....=14963&p=917316) , so, I won't repeat it again here.
There's really no hard facts saying that NH+SS were a much bigger fanbase. Seriously, no one knows exactly. Not even the publishers it seems... and it really doesn't matter anymore at this point, because everybody knows they turned out to be the *least* contributing fanbase to the bottom line. Boruto series is built on top of NH+SS as foundation. Last time I checked, their first week manga volume sales is not even 20% of "normal" Naruto series first week sales figure before the last volume. These are facts. It's out there in the internet, you just need to search the information, and piece together the puzzle.
Would they make a better profit if they continue with the plot consistently and make an open ending on pairings end? Yes, I would think so. At least it won't erase 80% of their current sales (which is the current state with Boruto series ).
Would a franchise reboot fix this problem? No, I don't think it will. It's a one way ticket, and unfortunately they've made the wrong bet. Either way it's going down, but the decision to make NH+SS canon only accelerates that decline... sadly. Not only they are having difficulties to capture new audience, they've also wiped out a hypothetical 80% of their sales, prior to the new direction.
Everybody knows manga industry has been declining since long time ago. I'm not sure about you guys, but I'm old enough to follow the trends over the years... ha ha... anyways, some of the articles that I saved in my favorite folder (yes, these are old, but if you have been following, the industry is still declining).
http://usatoday30.us...-18-manga_N.htm
http://io9.gizmodo.c...ould-get-better
http://www.bloomberg...inancial-advice
Key takeaways from these articles:
- Manga sales peaked in 1995, at the end of the Dragon Ball saga. It never came to the same level since.
- Younger readers downloading digital content are mostly female (about 70% of it in Japan in 2007). The most popular story? boys love (yaoi).
- Many believed that the new home for Manga industry is in US (population decline in Japan is slowly draining the pool of potential readers for manga, which is young people / teenager). We all know how it went... To sum it up, the manga sales in US peaked in 2007, where it hit $210 million. In 2014, it went to $75 million.
So, you can conclude it yourself, why Naruto series took such directions, and throw away all the promises it held in its earlier days.