What they need, is a marketing campaign. A "planned course" for an ongoing period of time. The fact they've taken down their older games from Steam and console markets had not helped, unless they're going to release a "Shinobi Origins" like they did with Sonic.
Unfortunately putting old games as compilation won't attract new fans.
Take example back then with Sonic Jam for SEGA Saturn, it didn't attract many new Sonic fans in Japan eventhough SEGA Saturn is very popular there. Sonic Adventure and Sonic Frontiers are the games that attract many new Sonic fans in Japan.
Another thing I don't get is, if their collaboration with Retro-Bit is legitimate and the controllers they made are officially licensed, why not promote those more as well? Have Shinobi:AoV respond to six-button controllers, or Sega could commission Retro-Bit to make special promotional controllers?
Same reason with with above, doing that won't attract new fans.
Retro-Bit's target market are old SEGA fans who grew up with Mega Drive, Saturn, or Dreamcast.
Or, just put more promotional stuff on Sonic Racing CrossWorld or even Fortnite. I can't imagine Sonic in Fortnite, but various Sega characters, sure.
It's not Shinobi AOV team to decide what character that can be put in other games.
Plus Sonic Team has ran an official player feedback survey for Sonic Racing: CrossWorlds.
The survey allowed fans to share thoughts on game modes, rank, overall experience, and—most importantly for many—suggest which characters. If Joe Musashi isn't showing up, most likely because Joe Musashi wasn't on the top list. If I'm not mistaken, Arle and Miku were indeed the most requested ones back then.
I know SEGA did try their best to market Shinobi AOV though. It was always showing up in every game and anime convention.
But during that time SEGA's also promoting Persona 3 Reload, Metaphor: ReFantazio, and Persona5: Phantom X, and those three games garner more attention and interest than Shinobi.
