I've also had my mentors strongly discourage me from doing a PhD in Physics, despite my ability, because of how overly saturated academia is with physicists and how I will have lost money to the order of half a million or more while returning to the same exact salary and salary cap after the PhD is finished.
Anyone who thinks that a PhD is the fastest way to riches needs to have their head examines (by a PhD).
This is largely what I would expect. A PhD (actually, anything after the Master's) isn't really about acquiring new technical skills. It's about learning to put into practice the basic values that sustain the discipline, which in science consist largely of 1) a fanatical obsession with figuring out what the data is really telling you, 2) relentlessly questioning your hypotheses and entertaining alternative explanations, and 3) rooting out the various cognitive nooks and crannies wherein lie the temptations to fool yourself or others.
For most technical jobs, these kinds of habits are not really germane to what you are being asked to do. Hence many businesses are quite reluctant to hire people with PhDs at all. The ones they do pick up will tend to agree that their PhD was a "waste of time."
Yes, academia is competitive, and unforgiving, and harbors a lot of eccentric and even ugly personalities. But the fact that it is "all about the discipline" is part of the appeal. And society cannot afford to sustain young people at such a high level of intellectual freedom with anything more than a "basic income" at best. Most of the things that make academia difficult are part and parcel to what makes it special.
The biggest change I would potentially advocate is an email to all first-year students letting them know that if they just want to take classes for a few years, get a cushy job, and drive a Lexus, they should be in medical school instead.