It is understood that comic book fans are trained to be traditionalist, The big comic companies train you be like that because they make money on OLD and new stuff. Manga fans are more trained to seek out new good stuff, After you finished your favorite manga you probably started to seek out a new manga. Fans can be "trained" to appreciate new characters it just takes some effort by the publishers. Undoubtedly characters like Wolverine, Cyclops, Storm and Magneto are extremely popular and it is hard to imagine any character equaling or passing them BUT that status does apply to every older character in the franchise. And one of the biggest problem that exists for the X-men is that it treats Banshee, Colossus, Iceman, Havok, Dazzler, and Angel many other characters like they are those first group of characters or fail notice when characters like Beast, Nightcrawler, Gambit, Storm,Kitty or Rogue have grown stagnant in stories and need a long break. X-men books have spent too much time trying recapture old magic than trying create new magic with characters like Sunspot, M, Magik, AoA Blink, Moonstar or X-23 who are on cusp of bigger stardom.
You can make an argument that hey new characters can't surpass Wolverine and Clops but we have seen characters like Bishop, Gambit,Jubilee and Cable pass or equal Angel, Havok and Dazzler in popularity. We have seen Magik, X-23 and Emma Frost do the same as well in recent history. Magik is easily more popular than Colossus today and it is going to be even bigger after New mutants movie. Magik big growth came as member Bendis X-men run where fans got to see her as
real X-man, Emma Frost growth came as member of Morrison X-men where fan got to see her as real X-man. For characters to catch on they need significant roles in significant stories and form significant relationships. The success of Emma and Magik partially comes from interactions with Cyclops. Magik has interesting friendship dynamic with Cyclops that can be explore in stories. No new character is catch on with out a hook to another main character, so every time you see new character put a team and in background it is pointless.