I'm going to comment on something entirely outside the details of the crash, but still likely relevant. I have to go back to ages ago, when I was studying psychology and recall the section on something called 'successive reinforcement'. One can just google it, but how this becomes an axiom of that profile is this:
First flights with the new plane... Everything is double checked, every i is dotted, and every t is crossed. We have a successful flight. Next 10 flights, everything becomes normal, everything is foolproof, all flights successful. Then, over time - one little, inconsequential item, maybe a T/R didn't work, and the flight went just fine. Maybe the anti-skid showed a fault, and the flight went fine. Next, we have a perfectly good single pilot type plane, and we have a single pilot with mega-hours. Several flights, everything goes fine, safe flights. We begin to stretch the rules, only slightly at first, then things start to pile up. Electric problem, single pilot problem, weather problem, ATC problem. We've been cheating the rules a little bit here, a little bit there, and successively gotten away with it.
The books on successive reinforcement are usually discussing a positive swing of reinforcing a positive trait or theme, or action(s). In this case what I see is an operation that has gotten ragged over time, and over successful flights until the holes in the swiss cheese began to line up right. Which leads to the inevitable 'what if' possible breaks in the chain. I doubt the NTSB will have anyone on staff with this kind of background in psychology, but it might help in cases like this.