Not likely to happen, but even if by some sort of insane change in the cosmos YG himself steps down as main figure of the company, his brother is likely to take over a similar position, if not as the main visual figure as YG has been but more as a simple CEO/main shareholder or it will be the type of figure that is backed by another large conglomerate outside of YG Ent itself (similar to Fantagio being taken over by a Chinese company that has essentially FUBAR'd the company).
The fact that so many people are already leaving the company currently and so many more are against it given the stigma it has had for a long time, especially with the newer incidents, rumors, accusations both of artist and YG alike (and even some direct company issues as well, like use of funds via company for illegal activities etc), it will be interesting to see just how long the company can stay afloat.
I have a feeling nothing too grand will happen - people will disassociate the acts they like (BlackPink, Lee Hi, IKON etc) from the company, as they should since acts are not directly their funding company, and the world will go on. It's curious to see, though, once contracts come up....who might stay and who might go, especially soloists and acts not associated with YG-built groups.