... and so on. PID is nice since it's idiot-friendly.
(And even with a Ph.D and a complete understanding of all of the above, it's often more fun or efficient to be an idiot and just use PID; I've never seen a place where PID was the right answer, but it's oh-so-often a good-enough answer)
Ph.D means you're doing something like:
* H2-optimization and optimal controls
* System ID
* Intuitive classical controls (Bode obstacle course, Nyquist, root-locus, etc.)
* Fancy discrete state-space methods / search / shortest path
* Machine learning, and the thing training itself
... and so on. PID is nice since it's idiot-friendly.
(And even with a Ph.D and a complete understanding of all of the above, it's often more fun or efficient to be an idiot and just use PID; I've never seen a place where PID was the right answer, but it's oh-so-often a good-enough answer)