[axiom]

Here's the thing about giving talks: people will remember only one or two things you actually said. As a result the approach one should have to putting together a good talk is totally different than the approach you should have in writing a good essay.

In a good talk you want to have one central point, repeat it half a dozen times, and pad it with a whole bunch of very memorable concrete examples. That's the only way you're going to make anything stick - otherwise people won't take away anything.

So the goal isn't to pack as much info and wisdom into a talk as possible - it's to pick that one central point and try and get people to remember it.

This is of course totally different than an essay where people reading it tend to be less distracted and have time to read it over if necessary. So you can be more liberal with how much information you're trying to convey and how complex the idea can be.