An odd thing about all these technologies is that they are severely dumbed down versions of unix software that exists for decades. How is it "cooler" to write markdown instead of troff? "Dropbox" instead of <strike>nfs</strike> rsync? Text files instead of a database? Node.js instead of "insert generic server here"?
Maybe people consider that 'hip', but I don't see how any of these 'trends' have any viability for more than, say, 12 months[1]?
I agree with where you're coming from, and I'd certainly rather use, say, rsync to move content to a server than Dropbox (which, given their security track-record, is just asking for trouble), but troff doesn't really solve the "perfectly readable formatted plain text even before processing" niche that Markdown does.
Markdown has also been around since 2004, so it's outlived the 12 month "just a trend" horizon by quite a bit.
But isn't it by definition impossible to expect that plaintext can replace a markup? (I just wanted to use a strikethrough; can markdown do that?). That's just a niche for developers. Also i believe markdown just started its hype cycle: http://www.google.com/trends?q=markdown
Markdown isn't a general purpose markup syntax. It's a niche solution to the smaller problem of "I want to format a plain text file or plain text email in a way that is perfectly readable as plain text, but also can be converted into a web page that retains the same basic formatting".
Maybe people consider that 'hip', but I don't see how any of these 'trends' have any viability for more than, say, 12 months[1]?
[1]: http://fashion.about.com/od/latesttrends/a/trendover.htm