> Having good ideas is most of writing well.
> (...) it was a revelation to me how much less ideas mattered
> in speaking than writing.
What you're suggesting may apply to your personal approach to writing and speaking. As you mention, you feel much more comfortable expressing your thoughts as essays. That's great. There's absolutely no further conclusion we can draw from that.
Frankly these seem such commonplace claims that I think
more people would accuse me of wasting the reader's time
with platitudes than saying things that are false.
For the sake of completeness I'll defend them anyway:
1. You can't explain something clearly if you don't
understand it yourself. Your writing may be fine at the phonetic level, but you won't for example be able to use any metaphors. Your audience will feel like they're being driven in a Ferrari over ploughed fields.
2. Who is generally considered to be better able to
cause people to believe mistaken ideas, speakers or
writers? When you imagine a demagogue, for example,
do you imagine someone speaking before an audience or
sitting at a desk writing?
You're both right and talking passed each other. Writing and speaking both have their flourishes. Writing has constructs and techniques that are not strictly necessary just as oration does. There are also factors besides the content that affect the results of both mediums: writing something in my notebook does not have the same effect as posting it to my blog. So, as far as the tools available, writing and speaking are on the same level for recording and sharing ideas.
However, people are more susceptible to spoken word. There is a reason that poetry is read aloud. This can be used for good or evil but it does encourage people to spend more time preparing for the "flourishes" of speaking than the content.
I don't think anyone in this thread fundamentally disagrees with those statements :)
Your #1, at least, applies to both speaking and writing. In fact I'd think it applies more to speaking. Think of teachers and lecturers who can explain things with analogies on the fly, vs. those who just repeat things at the same level.
I think it is far rarer to see a flashy writer than a flashy speaker. Malcolm Gladwell is the only one that springs to mind. I think it's actually very hard to pull off as a writer.
This is precisely because of the 'other channels' you mentioned. It's very easy to spot someone trying to pander in writing, where in a crowd you get swept up in the general agreement of the crowd, it's an effective tactic that you often can't pull off in writing.
OTOH people who like him tend not to like Dave Eggers, and vice versa. I personally love Dave Eggers.