I do better than my psychologist friends, I guess

Both in the input (suggesting that Commercial Pilots need only 4 years of 'education' and no training or experience to begin working, for instance), and the output — ignoring the compounding effects of significantly higher hard-dollar compensation earned by those who have invested more in preparation.

Basically the notion of the 'units of preparation' (or whatever they call it) is not a particularly meaningful measure.

As a practical matter, it generally takes an aspiring pilot several years as an IP to get a job as a private jet pilot or freight pilot. That said, one can, in theory, rise very quickly up the piloting totem pole if you have the money to pay for instruction and rental hhours.

That's one of my trades, and if he thinks the short training time is what makes it pay off, it isn't. It's working seven days a week at 12-16 (sometimes more) hours a day. Boiler companies like National or RMR are among the best to work for pay-wise because they're the most miserable companies to work for because of the hours and the expectation you'll come off a 100+ hour week and immediately drive 500+ miles to the next job, which is why I don't do it anymore.

*Yes, I know there are boilermakers retained by plants/mills/factories that stick around for long periods of time on maintenance and don't work those kind of hours. They also require a ton of experience and don't pay enough to make this chart accurate.

If you divide annual income by training time, you'll come up with all sorts of things, but they're not a meaningful measure of anything. I agree with MrModerate's claim that it's badly flawed.