The book "The End of Averages" by Todd Rose was misquoted
First of all the exact quote from the first paragraph of the book was this:
At its worst point, seventeen pilots crashed in a single day
There is a huge difference between crashing and dying.
Anyway, he (Teimann) got the sequence of events wrong, but the general gist of what he said follows the intent of the book.
The crashing planes in the study were the in the 1940's. We're talking about planes like the P-80 and possibly the F-86.
That was the first generation of jets and they had many many problems in design.
Here's where the average pilot comes in. Those planes (the 1940's) had been designed for the average pilot's size as measured in 1926. The cockpit was non-adjustable, so The Army/Air Force sought pilots whose size fit the planes, but only that person who matched the average 1926 pilot would fit properly. In the highly demanding jets of the late 1940's, a pilot that didn't fit could have problems when split second control reactions were needed, and those planes needed it.
The study conducted by Lieutenant Gilbert Daniels in 1950 which examined modern average pilot sizes, was completed in 1952.
The upshot of that study was that the Air Force immediately decided to take the study's recommendation:
Everyone is different, and to get the maximum performance from people you adjust the environment to the soldier, not the soldier.
The Air Force immediately mandated that the manufacturers make many elements of the cockpit be adjustable for the range of sizes from 5% to 95% of men from the seats, to pedal positions, to belts, and helmet straps, and so on. The result was that pilot performance soared and the US Air Force became the most dominant air force on the planet.
The book gives other example studies and goes on to say
Any system designed around the average person is doomed to fail
This is the gist of the book and what Michael Tiemann was getting at.
Anyway, the summary implied that the generation of planes designed in the 1950's were a generation of pilot killers.
The 1950's planes had the cockpit fit problems solved.
The crashing planes were in the late 1940's. The study was begun in 1950. Obviously, those crashes were not combat-related. Those planes were demanding and possibly evil, and a bad-fitting cockpit made it worse.