Gaining executive attention (and keeping it)

I have spent many, many hours talking to executives, and those seeking to influence executives, about why process-based management is a vital topic for executive consideration. Everyone agrees that someone should be doing something about processes, and indeed quite likely they should be doing a lot more, but the subject seldom makes it to the agenda of the Executive Committee or the Board. It’s an SEP.
Why is it so? What can be done about it?