The Cape Verde season hasn't been that pronounced - looks like steady wind sheer almost to the Leewards that inhibits development. However, also note that TD10 dissapated in almost the exact area that TD13 dissapated - but the disturbance held together enough so that it joined with another disturbance in the Bahamas and became TD12. Which in turn became Katrina.
The same thing has been happening all yr. Almost every storm originated in Africa, but waited to develop till it was close to the U.S.