I don't think that's really fair, considering Miku only does like 300,000 sales at most, 7th Dragon is on it's fourth game and hasn't managed more than 150,000 in any release. Sonic and Phantasy Star aside, SEGA Japan's biggest series Yakuza barely breaks past 600,000 units in it's homeland, so it's not like their expectations are crazy high.
That's all the more frustrating, though. I know i pulled the old "THEY ONLY MAKE AAA GAMES" argument but they've actually do a lot of mid tier projects with a specific niche. So why the fuck do they pull the "no sales" angle when it comes to a series that's established as their flagship rail shooter series? It's not going to sell much, just make a game according to their expectations, it's how they make Yakuza work. It's a fucking good looking game and it has top notch gameplay but it's obviously a cheaper game compared to GTA or Final Fantasy. Basically what George said.
Except the bit about Crimson Dragon. Once again, that game was sabotaged by Microsoft in every way that counts, whether you're talking about how they forced the game from the 360 to a launch Xbone game, killing the install base to shit, or how they completely butchered the gameplay by forcing them to make the game based around motion controls since Kinect was totally the future or how coupled with both these facts, add a console launch so universally shitty, it made the PS3 look good in comparison. Literally every factor was against it and not necessarily because of the devs themselves. The patches were stretched out in a big period of time and they basically only fixed on thing at a time. It's a pretty good game now but the damage is done. If anything, it's a good case study that showcases everything you shouldn't do with a niche title to begin with.
I don't think there is much of a market for a rail shooter, I mean look at Star Fox Zero, we all just want a basic rail shooter like the N64 one but their adding all this nonsense that people don't want to make it 'fresh'.
That's all optional crap that Nintendo loves to add just for the sake of giving the idea that they're still "innovators". They did the same thing with Starfox 64 3D but retained the basic controls that made it so great. Starfox 0 has those shitty gyro controls but its main controls are classic. They even hired Platinum Games to help with the core gameplay. I'm not worried about Starfox 0, it looks like a great return to form after all those shitty ideas they had for the series.