The old Pian en Luries on Dwilight was a great way to look at this question, as there each member of the Realm Council was clearly a powerful and self-interested character (I mean that as a compliment
It actually led to a weird sort of balance where no one was really eager for a rebellion. Ultimately though, the answer is simple enough.
If you include Dukes, as members of any Realm Council, it goes to them. Once you're in place, you're untouchable. A good portion of the realm is loyal to you. You have the ability to leave the realm and join another, or start your own. You rake in the gold (and can rake in more through inventive use of the Duchy tax system) while never having to face reelection, or if you do, having the best recognized claim.
After that, it goes to the Rulers. The biggest part of that is appointments, not just to Imperial Regions and Cities, but to Realm Council positions for life, if the Ruler so chooses. Easy answers, if you ask me.
Finton.
