Fairly sure that a different article discussing the same book was linked in the Int Cell a few days ago. One of the best lines in THAT one was a quote from a Major General along the lines of "The quality of the men under our command allowed us to dither for longer than was sensible".
Have just re-read the article. I think his point was that the Army was a lot more "Darwinian" back in the olden days than it is now. And no doubt there were plenty of senior officers who were sacked and disappeared without trace. I am not sure that the Fredendall example is the right one to back up the argument, that's all. Fredendall was instead promoted on return to the US, and presumably thereby viewed publicly as a successful commander in war, whereas he had in fact been just the opposite.