Here is one answer.
This is pretty simple and dramatic. More money, less chance of being unemployed, with a PhD or Professional degree. This is true at any level of educational attainment, with the least employable, the least well-remunerated being those without high school diplomas.
Those with professional or PhD level education enjoy what is basically full employment. Even the bad academic job market in some fields does not make a statistical dent here. This being said, should you ge a PhD in a field with abysmal job placement at a mediocre state school, if your only dream is tenure at Princeton? Probably not.