Am making a constructive comment here to this most interesting (mostly discussion) of very difficult terrain:
(a) Peak to Creek at Whistler when it is not groomed for a few days or so, and the spring freeze thaw is in, is not very steep, but is a shade above 5000+ft of vertical with rock hard bumps/natural moguls for a little over non-stop, no-bail-out 4+ miles. I would contend that is one genuinely serious endurance run, and in the spirit of the poster who championed Stowe Mogul runs as being physically demanding, I would wager that if anyone can ski those 4 miles of hard moguls non-stop without a breather, they are amongst the fittest I can think of. BUT it's not scary, and it's not intimidating, it does not instill fear, but sure one can get injured or go into cardiac arrest on the way down from loss of lung power, or ejection on some mogul from poor technique or sheer fatigue, not fear though! Note they have benches helpfully placed on the side for those about to lose control of their bodily functions or their legs or lungs or heart from fatigue or sheer exhaustion !-)
(b) Here is an education clip I think of one of the undoubtedly greatest downhill world and olympic champions struggling free-skiing in Verbier. So even the best of the best get into trouble on genuinely steep, dangerously exposed terrain with the usual rocks and all that thrown in: Didier Defago on YouTube
(b) and the North and South couloirs(long chutes?) of the Aiguille du Midi which I believe a few on this site may have skied are steep, no ifs and buts and talk about fear factor...:
(c) One thing I have noticed for sure out West, on the Double Diamonds or Extreme trails or just seriously steep terrain, when the snow cover is thin, or it's frozen, there is not a soul on them, expert or novice, good sense prevails, the steepness and risk levels too high for injury or worse clearly. So by that measure, a lot of seriously difficult double black or whatever in the East gets skied, and folks do take a serious tumble and break limbs and worse, but by and large, it is attempted often enough because the perceived risk and threat to life and limb is perceptibly less. Just my judgment watching better skiers all across the places I have skied.
(d) And finally, a question of sorts to the Whistler Pros. I was told the Sapphire Chutes, down from Sapphire Bowl into the Blackcomb glacier valley runout (below Spanky's) are as steep, if not steeper on a more sustained basis, as False Face - and downright scary, just exposure more open on False Face, so that creates major fear factor - anyone please comment.