I don't think question A: How do you identify programmers who finish things? and question B: How do you identify programmers addicted to novelty/who have a hard time internalizing business goals? are equivalent or even similar.

Many developers are "addicted to novelty" because that is how the industry works. You don't get very far in the game by only knowing VB.NET and C++. To get a high salary you need to change jobs many times. To change jobs many times you need to have knowledge about the latest and greatest (AJAX, jQuery, MongoDB, TypeScript, Android, iOS, Rust, Go, Scrum, TDD, whatever...).