Spot on MadCapellan except you ignore the obvious conclusion that lead to the creation of the Blakist Protectorate and the Republic of the Sphere in canon. The Hegemony worlds became a battle ground for the Houses. Ground zero for the Succession Wars. Their central locations became prime targets for enemies to lash out at each other which breed more destruction. These central worlds of humanity went from the highest population centers at the nexus of almost every trade route to bombed out shells worse then Amaris left in his wake. Continual fighting over these worlds lead to resentment against the Great Houses by a people who remembered far better days of self rule. Enter the Blakist and Stone - the results speak for themselves.
True, but you literally just went fast forward two centuries, with what - something like 10-15 generations of people in-between and a handful of additional wars. (One generation being roughly 20 years. That might be a little generous by the 31st century.)
And your rational is not an obvious conclusion. The people of the old-Hegemony don't "remember" squat. They do however, see the bombed out, irradiated cities of their forefathers on worlds still habitable. A quick glance out the window says it all.
Joining the Word of the Republic is the simple matter of deciding what the next, best option for a prosperous future will be.
Remember, the Protectorate didn't just spring into bloom from the Chaos March overnight. The Blakists had to woo these worlds into the fold.
Phrase of the day: Enlistment with the best future.
