This is back up with the Matthew Stover Revenge of the Sith novel, where he says the Empire will last 10,000 years, and the Dark Empire trilogy where it was revealed he planned to keep transferring his essence into clone bodies to keep ruling the Empire anew from the shadows, and let his apprentices be the face of the Emperor. Similar to the God of Emperor of Mankind from Warhammer 40,000 now I think about it. Kinda. Here, look at this.
That also is consistent with Sith philosophy. Conflict brings out people's true natures. Especially true in the man who laid down the foundation for the new Sith order, Darth Bane."The Jedi Rebellion was our final test—it was the last gasp of the forces of darkness! Now we have left that darkness behind us forever, and a new day has begun! It is morning in the Republic!"
The Senate roared.
Padmé stared without blinking. "Here it comes," she said numbly.
Bail shook his head. "Here comes what?"
"You'll see."
"Never again will we be divided! Never again will sector turn against sector, planet turn against planet, sibling turn sibling! We are one nation, indivisible!"
The Senate roared.
"To ensure that we will always stand together, that we will always speak with a single voice and act with a single hand, the Republic must change. We must evolve. We must grow. We have become an empire in fact; let us become an Empire in name as well! We are the first Galactic Empire!"
The Senate went wild.
"What are they doing?" Bail said. "Do they understand what they're cheering for?"
Padmé shook her head.
"We are an Empire," Palpatine went on, "that will continue to be ruled by this august body! We are an Empire that will never return to the political maneuvering and corruption that have wounded us so deeply; we are an Empire that will be directed by a single sovereign, chosen for life!"
The Senate went wilder.
"We are an Empire ruled by the majority! An Empire ruled by a new Constitution! An Empire of laws, not of politicians! An Empire devoted to the preservation of a just society. Of a safe and secure society! We are an Empire that will stand ten thousand years!"
The roar of the Senate took on a continuous boiling roll like the inside of a permanent thunderstorm.
"We will celebrate the anniversary of this day as Empire Day. For the sake of our children. For our children's children! For the next ten thousand years! Safety! Security! Justice and peace!"
The Senate went berserk.
"Say it with me! Safety, Security, Justice, and Peace! Safety, Security, Justice, and Peace!"
The Senate took up the chant, louder and louder until it seemed the whole galaxy roared along.
Bail couldn't hear Padmé over the din, but he could read her lips.
So this is how liberty dies, she was saying to herself. With cheering, and applause.