I think blogging died when two things happened:

1. A blog became a required component in constructing a digital identity, which happened around the time that largely-static personal websites started to disappear. Blogs always dealt in the construction of identities, but until 2004, or so, they were just one tool among many.

2. Having a blog became the best, most efficient way for people to sell things. Blogging became a tool for selling goods and services, often on the basis of the reputation of the writer

As these shifts occurred, blogs stopped being things that individual people had, and started being things that companies created to post updates, do out reach, and "do marketing." At about the same time, traditional media figured out, at least in part, what makes content work online. The general public has become accustomed to reading content online. The end result is that blogs are advertising and sales vectors, and this makes them much less fun to read.

When blogging was just a thing people did, mostly because it let them present and interact with a group of writers better than they could otherwise, there was vitality: people were interested in reading other people's blogs and comment threads. This vitality makes it more interesting to write blogs than pretty much any kind of content. The excitement of direct interaction with readers, the vitality of blogging transcends genre, from technical writing and documentation to fiction to news analysis and current events.

The vitality of blogging is what makes blogs so attractive to traditional media and to corporations for marketing purposes, so maybe you can't have the good without the bad.

Everyone blogs. And perhaps that's a bit of the problem: too much content means that it's hard to have a two way conversation between blogs and bloggers. Who has time to read all those words anyway? Blogging is great in part because it's so democratic: anyone can publish a blog. This isn't without a dark side: we run the risk of blogging without audience, or without significant interaction with the audience, as a result of the volume of content which threatens the impact of that democracy. But it makes sense, New forms and media don't solve the problem cultural participation and engagement, they just shift the focus a little bit.