I somehow get a feeling that if the prospects were actually good in any sense, colleges would advertise them whenever they had the chance (is there even reliable information about how salaries are distributed? Not just means and standard deviations).

I got an undergraduate degree that has 0% unemployment rate with good salaires because there are so few graduates, but for a PhD (that I was thinking of getting) there is no guarantee that even the places where I would work are good enough in terms of research or teaching.