Yes, iirc the concept wasn't to decouple content and presentation but to decouple semantics from presentation in order to re-present content in different media in that medium's native representation of a particular semantic. However, many things are not much different in different media, a headline is a headline. And other things like "emphasis" can have cultural differences even within the same media, like being bold, italicized or even double-quotes.
I suppose to a limited extent, that being “articles” in the typical sense, the strategy might be said to have some modicum of success. I’m sure many CMSs store articles as mostly “plain” HTML and regurgitate the same, directly into a part of the final HTML document, with actual normal CSS rules styling that.
