The problem with announcing Future Tone more quickly relative to the other games is that they would have announced it before the release of X, which would have been awkward. It's possible that they might be trying to position the game for release later in 2017, especially if X is the last game in the series (the trend in sales for this game in Japan is... not good).
The reason I brought up fighting games was more for the point about how the majority of the market doesn't import. It's still something that publishers have to worry about (especially with the number of copies they're dealing with -- losing a few hundred sales may have an appreciable impact). Furthermore, that's not a genre that's a stone cold lock to be localized either, especially for the more niche games. Just in regards to recent releases, DBFCI wasn't localized (and that wouldn't have gone over well) and Koihime Enbu and Blade Arcus were not localized until they got PC ports.
I do agree that the single biggest hang-up is going to be the song licensing, and that really comes down to the specific terms Sega negotiated and how streamlined that process is -- and that's something nobody here is going to know. I think the US Round 1 locations are an interesting data point here, since they can run the game in California and Texas but nowhere else (as even the newer CA and TX locations have cabinets, but nowhere else does). So it shows that the licensing is practical at some level... but that's just a weird situation all around.
I still think it's an incredibly dicey proposition to go through the trouble/expense (whatever it may be) of licensing everything just to release the same game a year after it was released in Japan on a region free console. The timing is definitely unfortunate, though it's just the latest in a long line of decisions made in Japan with no consideration at all for overseas markets (DBFCI being a glaring example of this).
I really don't get the argument that rhythm games aren't an import heavy genre. The genre as a whole has not really caught on at all here; for a very long time, if you wanted core rhythm games you had to import. And that is still true for pretty much every rhythm game that doesn't tie in to some other property (Hatsune Miku, Final Fantasy, Persona, etc.). DJMAX and Superbeat XONiC were the only ones in recent memory crazy enough to not rely on licensing or tying themselves to another franchise, and both games kind of bombed.
Also, the Round1 case is indeed peculiar, especially since the English Project DIVA Arcade website actually bothered to remove the link to the US locations page (although it
remains orphaned and the locations list even updates to list the locations that opened after the English website stopped updating). Note Illinois is also an approved territory, being the three states Round1 operated within when whatever deal they have with Sega was struck.
Having a blast with Diva X on the Vita.
This game as a PS4 only title, means no more Miku games on Vita from now on?
Future Tone is an arcade port, which is why it is PS4 only. It's not exactly related to the mainline series; different producers and development teams. I would imagine the Vita is actually still the lead console for the mainline team, given how much bigger the DIVA X Vita release was in Japan (whereas the PS4 release was sent out to silently die).
