Well yes, it's a vague term, just as "yield management" was when it was introduced 30 years ago or whenever, but I suppose the idea is the same -- extract more miles from customers on flights where there might be higher demand. Saver/Anytime is probably the most basic form of dynamic pricing, then they added extra Anytime levels. Arguably it already exists.
Agree that advance purchase could come into play, that's another extension of peak/off-peak, day-of-week, etc.