After some research, I really think that YG's mismanagement, followed by Minzy's exit, caused the disbanding in the long run.
CL wanted to take the group to the US after her solo debut. YG agreed because he thought the band wouldn't perform as well as usual in Korea because of Bom's scandal. CL, Dara, and Bom were already fluent in English, while Minzy was not, and sources say she lacked of passion for singing in English, so the recording process for this project began to stumble and eventuelly stopped.
2NE1 was stuck in their hiatus and Minzy decided to open her own dance academy. The group reunited for the last time for the MAMA's 2015 performance. Months later, Minzy announced her departure from the band.
The remaining 3 members wanted to go on as 2NE1 and another album recording process started (probably the one in summer where CL left everything behind and flew to Korea.) The problem was, that YG was very dissatisfied with 2NE1 as a trio and wanted to replace the missing member with a new girl. This was no option for the girls and they decided to disband.
Hmm interesting read. 
so much potential
oop
