If I remember correctly, the key case study in Change By Design (that started he whole Design Thinking movement) was Nokia Ovi. So even ‘might work’ needs to be put into a time bound context. At the point when Brown wrote the book it was ‘working’, and there were claims in the book how Nokia is reinventing itself driven by design thinking, but then the whole ship sank soon after.
my understanding (without research) was that one of the founders of IDEO created the concept so they could broaden their client pool from traditional design to finance / business consulting.