... isn't to try to make people change ... it is to do something that can't already be done.
Don't try to get your powerful people to behave differently - they have everything to lose. Don't try to improve your existing processes - you will be seen to be breaking something.
Focus instead on the things that are desperately trying to happen but aren't and the people who are desperately trying to connect but can't. Do things that make the impossible possible and your success rate will soar.