The only real rot I see in the PhD track is the dangerous imbalance of degrees to jobs in certain areas (not STEM usually, although STEM is pretty uncompromising for tenure track). IMHO in the humanities the PhD is some kind of sick ponzi scheme, where advanced degrees serve to subsidize tenured faculty's careers with little to no hope of going on to anything of their own. (I know STEM isn't much better, but it's a little better, especially with industry being willing to assume some risk.) But I've got friends $100K in debt for an art history PhD, and that's craaaaaaaaaazy given what awaits on the other side.