Salaries for healthcare professionals decayed substantially in the 70/80's which resulted in a lot of people either leaving or chosing not to join the healthcare industry. In the 90's a shortage began to develop and salaries have been on a upturn ever since (and by heatlcare professionals I am not refering to doctors). Teachers would be another example, there are loads of other examples out there.
Pilot salaries are in the toilet because there are way to many pilots and way to many people who want to be pilots (what other industry do people PAY to get a job). Couple this by having far to many planes in the air and the economics lead you to only one conclusion, ground planes, cut salaries, and fire pilots.
The turn about will be though that in 5-10yrs because people have fled the industry, not started in the industry (and everyone posting here keeps telling new people to forget even trying to start in this industry), and retirement there is going to be a pilot crunch. This will drive salaries up.
I don't know what else Pilotyip maybe right or wrong on, but he is correct that in a couple of years salaries and demand for pilots will surge.