Wordpress used to be that but it's turned into a huge CMS that's trying to do 2000 things at once. Jack of all trades and master of none if you will.
Wordpress isn't? Unless things have changed you install it and start adding blog posts.
That's what ghost is. It's a blogging system without all the added bloat and horrible API's to go with it.
???
1) Log into admin area (usually /wp-admin)
2) Click "Posts" on left sidebar (first icon on the top)
3) Write
4) Submit
What do you mean by "setup and run"? The work setup is extremely elastic. WP is setup and run. So is a particle accelerator, as is a fridge.