I would thank you, my supercilious friend, to not fucking put words in my mouth, okay? What I am asserting is that it has not, "as a matter of fact", changed. You can point at Presidential elections as oh, hurr, shallow, and I'll even agree with you. And then I will point at Obama's convention speech in '04 or even Bill Clinton's in '12 as modern examples of long-form rhetoric. Because that stuff happens today, too. And people watched, and listened, and talked about those, too (but they had the temerity to talk about it on Twitter, so I'm sure it didn't count).
Lincoln-Douglas looms large in the retrospective eye because it was important (and was at the confluence of a number of factors, not the least of which that it was a geographically diverse set of venues but mass communication was still the newspaper and the telegraph). Perhaps it is worth reflecting that modern presidental elections may not be so important--I mean, the gap between a right-wing and a center-right party is, on balance, very small--and the level of discourse may reflect it. Consider also the consular elections of the Roman republic during times when very little of importance was happening. They're venal, they're often populist, they're regularly pandering and stupid. They look like--well--today's. Because nothing is as stupid as fights when there's nothing of meaning to gain.
I mean, shit, dude. You know what came most of a century before the Lincoln-Douglas debates? A little speech by a dude in a church in Richmond. It's about fourteen paragraphs long. I've read it. But there's one sentence from it that you actually know: "give me liberty or give me death." Patrick Henry laid the groundwork for that sentence. It's a good speech, if you care about that sort of thing. But nobody was reading it then (it wasn't published for forty years, and nobody's actually sure how much of it is the original speech). That sentence is what caught, because it is distilled sentiment and meaning and requires no attention span at all.
You are arguing against history as well as the tide, to heroify dead people and pretend they were other than how they were. I don't understand why.