Sadly you are correct. I guess at some point we should expect 3-4 different books with the Teen 05 (as that's who they want to push rather than their adult counterparts, two of whom are dead and one practically exiled from the X-Men, Storm, Kitty Pryde, Wolverine/OML, Nightcrawler, Colossus and Psylocke, who is another perfect example of a character that was filler and throughout several successive drops and climbs in popularity seems to finally be in X-Men A list status (as in always used.) Rogue too now that she appears to be back in the X-Men house.
Essentially they'll cut it down to some kind of iteration of the 90s 12 blue/gold team members (teen, OML, whatever iteration is a fill in) and Nightcrawler and Kitty. And basically say to hell with all the rest they "weren't/aren't/can't be" popular, where it then becomes a self fulfilling prophecy where they are never popular because they are never used, and are never used because they are never popular.
The only significant growth of characters not in that set we have seen over the last 17 years has been Emma, Magik, Cable, Deadpool and X-23. Emma is now off the plate, Magik is in limbo (no pun intended) and Cable Deadpool and X-23 have their own thing of course. Everyone else except for the core, and even some of the core, has suffocated and suffered. (edit: I will add Monet to this too under PAD and Bunn only though, and Madrox under PAD).
FWIW I'm not saying that cast isn't the core X-Men. They are absolutely the core X-men, along with a few additional characters. But that shouldn't mean that the core is the only thing that is used. It should just comprise a good part, maybe 1/2 to 2/3rds of what's being used and let the remainder be given some kind of opportunity of a chance to grow. That's why books like X-Force (90's) Generation X/New Xmen, and X-Factor (all after the O5 version). They were comprised of cast that was NOT core and there was absolutely a need for those characters to call a place home.