The mass infighting is destroying the Sith from the inside. Lesser Sith team up to destroy more powerful Sith, who in turn is defeated by even lesser Sith. This is a downward spiral that would destroy the sith, and it will. This is the reason the Rule of Two was so successful. Only the stronger could win, there were no allys to help.
Think of this:
Revan was dark lord. Malak destroyed him and declared himself more powerful. Malak rises, revan falls. The lesser takes control from the powerful.
Satele shan once said, "a united sith is a force that cannot be stopped."
But you see, they arent united they backstab, and it is the reason they fall, like all animals must.
No, i understood that. My point is that any form of government created using Sith policy is doomed to fail 100% of the time. You can't have a government made up of super charged serial killers and actually think it'll last, but the fact is that it CAN
last for awhile if 2 things are followed: 1. A leader who can take on any single person below him in rank. 2. Those below the leader are too busy working against their rivals to ally against the leader. As long as both of those are followed then it'll last, the problem is that it never lasts forever.
The only way a Sith could truely rule is if he got rid of all the jedi and other sith and controlled the government from the shadows. It was Darth Plagueis who actually thought of something like this, though he had different reasons. The strength of the idea is even if the "leader" is overthrown, the sith could just control the replacement leader, repeat as needed.