Blogging isn't dead. People will always want to say more than 140 characters but write less than a New York Times article.
However, the blog as exists on your own website may be dead. The only way to ensure your content gets read is by posting it on platforms, including Facebook, Medium or Tumblr where it can be reshared and discussed. Instagram can also be used as one of the large blogging platforms. In summary, fish where the fish are.
“Creating content on Medium is easier than doing your own website. So is getting readers. There’s an order of magnitude more people who have an inclination to share thoughts and ideas with the world than people who want to be publishers.” Ev Williams
But your blog can still be a starting point, a canvas for your ideas before you adjust them and crosspost your work on other sites. In this way, the blog becomes a way to show your work/process and the platforms become a way to package and ship your work.
Blogging is writing. If you're a blogger, you're a writer, professional or hobbyist. The large blogging platforms (re: social networks) are just a way to extend your voice.