Not dismissing any points above but just a personal experience (I was the Southern District VP for two years).
It is sometimes very hard to get a full commitment from speakers, especially the big speakers that you want as a draw. People say “Yes” but getting them 100% in place is hard. Even when they commit getting the title of the presentation and blurb for the topic material is like pulling teeth. This is one of the “fun” jobs of the District VP and hopefully the planning committee, who are also volunteers.