the average for completion of phd/psyd in psychology is between 5-7 years, program dependent. your acquaintances fall in the low part of the curve.
but you are forgetting the 2 year post doc for neuro.
5+2=7
7+2= 9
in my opinion, both times to completion are roughly around a decade.
the starting numbers in the sweet survey begin after post doc, so 2 years after graduation from the doctoral program. assume you graduated from undergrad at 22 years of age. and that you immediately went into a doctoral program. you'd graduate at 27-28 depending on when your internship ended. you'd then complete a 2 year post doc, with salaries averaging around 30-35k. that second year you would be licensed and effectively making approximately 50% less than the national average for licensed psychologists working in a non-private practice setting. then you'd graduate from your post doc.
assuming you immediately landed a job, at 29-30 you'd start making the national average for clinical psychologists (70-80k). 6 years later at age 36, you'd be making around 103k.
for all that work, the payout seems not so great to me.
let's then look at the opportunity cost: compare the salary to the loss of opportunity for working for 7 years. looking around, i would say that the average salary for an individual with a BA in psychology would roughly be around 35-40k/yr. so assuming you never ever got a raise, and that no benefits were given to you, and that you never invested a single cent, or bought any durable goods, you would be losing out on $245,000-280,000. then factor in any debt you get from going to grad school. let's be conservative and go with 1996 APA data: 40% had over 30k for school. so the opportunity cost becomes 275,00 to 310,000. subtract out the post doc and internship salaries combined, which i would guess would be around 95k. you are sitting on a cost of opportunity of 180k. this estimate is impossibly low as you would likley get a raise or make an investment or buy some consumer durable during this 7 years. however, making up for that low estimate would take a considerable amount of time, which i do not wish to calculate for you but would guess would be over a decade before you actually started earning money on the deal.
you could also do an ROI analysis. but i am getting bored with this and imagine the numbers get worse.
t4c might be able to give much better numbers, i think this is more his deal.