What drives innovation anyway ?

Is it passionate individuals or the drive from senior management leading to innovation or corporate strategy or is it the external environment.

In my experience on this subject I have had the privilege of listening and reading materials by innovation experts. There are various views- 1. There needs to be passion in what we do. 2. Need for senior management to drive innovation. 3. Innovation to be part of the corporate strategy. 4. Then there are combinations for E.g- we need passionate individuals and organization support. 5. If an innvation success drives more innovation. 6. Then there are people saying that even the innovators kind of relax if there are no challenges from the external environment. Following this line the same say that when the “survival of the fittest” condition starts to set-in, it becomes inevitable that there is a natural tendency to innovate which further leads to actually doing well to find ways to survive by innovating. However in the end, only the best manage to live through for the next cycle.