I don't think it is a coincidence that the mega blocks licenses are more "adult centric". I have a room of 27 seven to eight year olds, with both lego and some mega block (skylanders and other stuff) a parent donated last year. The mega block stuff, bar the figures do not get touched.
With all the Mattel license, I expect we will soon need a whole aisle dedicated to non lego building products, including knex which refuses to die quietly.