The Girl Who Played with the Dragon's Nest

Have you read The Girl with the Dragon Tattoo? If yes, then have you read the sequel - The Girl Who Played with Fire? and, of course, having read two you must have gotten to the final book - The Girl Who Kicked the Hornet's Nest. All three remain in the top 30 on Amazon nearly three years after Dragon Tattoo (english version) was released. 

So I have a question - why? 

The writing is not brilliant nor is the mystery unique. A New Yorker article attempted to answer the question: Why Do People Love Stieg Larsson novels? An interesting article that poses even more question than I have and informs us that Larsson may have planned a series of 10 novels with these characters but he died having completely only these three.

I think the answer has to come from the lead female character - Lisbeth Salander. With a Nazi monster for a father, victim of all sorts of abuse; childhood and contemporary, tough, smart, silent and a feminist of a very unique pedigree. The attraction to the books must be a strong affinity to the girl with the dragon tattoo.

For me the books were interesting beach reads, though I consumed them during this northern california winter. The setting in Sweden meant readers are exposed to a different corrupt government than Russia, China, U.S. or Vatican City; that was refreshing. You never get a really good dose of neo-Nazism at work in American novels.

But after the change of setting, the novels are not particularly well written politico-mysteries. No, it has to be the girl in the titles. Don't get me wrong, the stories are good, at times very good; but the delivery is weak. The New Yorker article summarizes all the controversy about who may have helped with the editing of Larsson's original drafts. There is much agreement that he had more than substantive editing revisions to get the books to their current condition.

But even with a gang of editors the books really are nothing unique. Not a single orc to be found, nor actual dragon to be slain or ridden.

Can someone explain this to me?