With all due respect Alf, you have a way of using some "big" words trying to almost "justify" this crews actions. As I said a couple of posts back, this was an "off the scale event" which needs, to put it bluntly, a severe reality check/correction for the individuals involved.
You ask "where the line is drawn"? Well, if you've programmed the FMGC correctly, put the descent winds in and the constraints you require/want in the descent, the aircraft will draw them for you! And it TELLS YOU it "ain't gonna work"......
BASIC training when you come onto jets is, typically, 3 x your height + 10nm to slow down for a "normalish" profile - these guys didn't even get close and no amount of what / where / why / how / fluffy can start to "soften" what they did.
The more I've thought about it the more "angry" I feel about it. It could be argued that these guys are the equivalent of the market traders who "bet the farm" in the hope it would come good but didn't and lose £x hundred million. The difference is that these characters had the potential to take 150+ soles to meet their maker.
It can be analysed to death - they screwed up and didn't sort it early - bottom line.
You talk of "dual failure" of cognitive overload. Overload, typically, only occurs in the latter stages. If you're 20,000' at 30d there is NO overload at that point. Any pilot with any NORMAL, EXPECTED "cognitive recognition" would say AT THIS POINT, "we need more track miles" - stress, risk, error, high workload - REMOVED.
Sorry to sound blunt - this was a totally unnecessary event. Macho BS/pride - call it what you like - no amount of psychobabble will ever justify this to me.