Hear that one used more for memos or emails, but same concept. Give people a sense of what's at the end so they see where the background is going. Use the story-spine if you want, but show a trailer to convince the audience there's some juicy explosion-ladden scenes at the end of the rainbow.
The Amazon method of starting with quiet reading may be the only solution…
I've had plenty of people interrupt me to ask questions while I'm presenting - which I think is generally something to be encouraged.
When I've replied with "That's a very insightful question, we'll get to the answer in a few slides time" I've never had someone insist on continuing the interruption.
Thankfully they only attended our meetings once a quarter and never involved in matters beyond pontification.
If you can’t wait them out, or if they’re the CEO, find a different job.
If they refuse to comply, leave.
That's what I want from others, so that's what I do.
Let the ego aside, be useful.
[1] https://en.wikipedia.org/wiki/Inverted_pyramid_(journalism)