Haha, I'm not sure where you got the idea that Steemit is democratic. ;) We already have the situation that the richest people are the ones who decide what content gets heard. It's important that we keep the incentives in place to make sure this pay-to-play is transparent.
My proposal is specifically to do this on a per-post basis; leading to what you call "a distortion of the curation market." I think that rather than distorting the curation market, it would simply raise the curation rewards - we'd end up with a setting where basically every post is offering X% curation reward, where X is some large number close to 100%.
I see, I was assuming your intent was that the curation reward was more like a bounty split amongst the curators. But I just learned that curation rewards for early voters are already split with the author -- which I wasn't aware of. So with that in mind, your proposal makes more sense.