Then what would be counter productive is to publish and waste time in trying 3 more other series to end up axing or cancelling them all because full focus is directed to Samurai 8. I'd understand it as a bit of both strategies, to get attention and hype thanks to Kishimoto's comeback and create a whole advertisement campaing for Samurai 8, and with all that gained readership, try other potential series with topics not-related to the main point of S8 like, in this case, sports. Even if I still think 3 more series is kind of a high number (maybe just 2 other series could have been okay), I don't think they are only focusing on the biggest series since it really doesnt need any kind of big promotion to succeed (like, lol, licensed already worldwide seems enough for me). It may end up as a complete failure if none of the other 3 series is able to get attention or they all end up being completely non-interesting, but that depends only on the quality they show.