>it's not a high school presentation
I agree, we can expect more from the presenters here.
Experts are humans, experts get bored, experts can't necessarily follow your bad presentation.
Underneath it all we're smart monkeys, not robots. You can't force yourself to pay attention indefinitely. It's not in our biology.
No matter how smart you are if you hear hours of presentations in a day, you will only take home a certain maximum amount of the stuff that seemed important.
If you're a presenter, and you have something life-and-death important to say, you should repeat it, you should put it into simple words, you should use appropriate language, voice and maybe even pictures to make it clear.