People have speculated for years about why f(x) dissapeared from kpop and was put in the dungeon after the enormously successful 4 Walls.
Members have stated many reasons why such as timing and schedules never lining up and how they were just waiting on the right project.
A theory I've heard about that makes sense is f(x) lives and dies with Krystal. And after SNSD kicked out Jessica that was the straw that broke the camel back. Krystal was DONE with SM. She held a grudge against SNSD and SM and then later one of her best friends leaves her own group. I'm sure f(x) was already half way done with recording 4 Walls album so that's why we still got one more comeback after this mess.
But Krystal knew deep down this was it for her. Shed always been a little distant as an idol but during 4 Walls promotion she was extra cold.
From the notorious end stage of SNSD where Krystal could be seen trying to sneak off (cause those dem hoez that did my sister wrong) to her also notorious I DONT GIVE A FUCK face during Mama award acceptance. She couldn't get out of kpop fast enough.
It all fell on Krystal. If she agreed to at least one more comeback after 4 Walls then it would have happened. No doubt about it.
What do you think about this angle? I'm not bashing Krystal either. I love her. But shit hit the fan for her with SNSD and I feel like it played a huge role in the fate of f(x).