[member="Mullarus"]
Saw the Palpatine reference, and here's a point I'd like to make. (Malak is part of it, but not -as- much which I will explain further below).
Palpatine killed his master after finally rising to the point where their plan could not be messed up anymore. Look at what Palpatine did after killing the man. He killed almost all the Jedi and took over the known galaxy. He had put himself in a position of power where Pelaguis was no longer needed.
Malak wasn't the same, yet was at the same time. He was still winning the war. Had Revan actually died instead of becoming that character we all know and love as a snowflake, Malak probably would have won. And had the galaxy under his control.
The Sith didn't just betray one another because they could. They did it when it wouldn't compromise their own integrity. If the Republic was winning the war against Revan and Malak, well. I don't actually know. But if Palpatine still needed Pelaguis, Pelaguis would have existed for quite some time, until he would no longer be needed.
The same is for the One Sith.
Ferus wants to make a Civil War for example. He wants to break the chains he thinks the One Sith currently have. But now isn't the time. The republic are almost beaten, but the Galactic Alliance has shown up. A new unknown foe that could and would take advantage of the Civil War to wipe both sides out.
tl;dr
Civil War will happen, but only when both sides won't loose from it. Sith are known for their treachery and self interest, and with whats going on in the galaxy right now they'd loose even if they won the Civil War.