I really think you judge way too harshly.
I don’t think narcissism has anything to do with it most of the time. I think people are using blogs to simply write for the sake of improving their skills, using the blog as a repository of their writing. This also makes their efforts available to the public for objective criticism. If the critiques are positive, they are encouraged. At the same time editors of small publications search the web for new writers, popular writers and pick up the ones they like. That’s how what’s her name who wrote 50 Shades of Grey and, no matter what you may think about her writing, she ended up with a best seller right out of the gate, two other books in print and three extremely lucrative movie deals.
As to exchange of info, there are a lot of people using their blogs to keep their friends and families informed of their status in lieu of Facebook. I follow many blogs written by individuals and families who are circumnavigating the earth on sailboats and cyclists biking around the world —sometimes in the most godawful conditions. They blog a few times a week, complete with maps, charts, photos and describe their daily experiences. These are very informative to other sailors and cyclists as to what obstacles they can expect in remote areas, etc. But most of all they are just damn interesting.
These serve as a personal journal of their progress as a future keepsake for the grandkids and exposes them to editors. I know of three women who are partially funding their circumnavigation through their photography and many sailors are doing the same writing intermittent articles about the places they go and their experiences for sailing, boating, food, general adventure and travel magazines, both on the internet and hardcopy. Solid western currency is a godsend in some of the places they go and spends very well.
One of my favorites is written by a Canadian woman, a grammar school teacher of only a few years in teaching, who opened her blog describing how her husband came home from work one day and asked her if she would like to spend the next few years sailing around the world. She describes how she had never been on the water at all and his only experience was sailing small dinghies on Canadian lakes when he was a kid. It took some convincing and a lot of research on her part and she decided to do it. A bloody recipe for disaster.
So, they flew down to Florida, bought a 52 foot sailboat, went sailing with the captain/teacher for a couple of weeks, parked the boat in the Keys, and went back home, quit their jobs, put all their stuff in storage, sold their house, flew down to Key Largo, stocked their larder, boarded their boat, and off they went into the Caribbean—with their four kids ages 2 through 9!
She wrote about the experience from Day One, the day he came home and pleaded to go sailing, how they planned it intricately for a year before buying their boat, details on their studies, prepping, stocking the larder, handling the kids all the way up to now when they are still exploring the Caribbean and prepping to pass through the Panama Canal into the Pacific. They both are writing for mags and she is getting paid for her nature photography. Nobody thought they would get through the first month, but they had an amazingly steep learning curve, confronted mechanical problems, the finer legalities of entering foreign ports of call—and at the same time she is home schooling her children through the Canadian school system. These people—all circumnavigators for that matter—are totally amazing. They are doing just fine now that they have a couple of years experience.
So, don’t judge too harshly. Many blogs serve a purpose far beyond massaging the ego. You can avoid the internet flotsam and jetsam by searching for specific types of blogs in subjects you are interested in.