I think the flaw in Jim's analysis is that it presumes that pieces of UL gear should be interchangeable with pieces of heavier, but more durable gear. In other words, he compares the two, discovers that lighter gear does not perform equally to heavier gear when placed in situations where heavier gear makes more sense, and concludes that this makes lighter gear inferior.
This all seems to have been triggered by Jim's new down parka purchase. He was expecting that the new parka would perform exactly like his old one, except be 10 oz. lighter. It didn't. It couldn't. The 850-fill down and the gossamer fabric were not enough to account for the 10 oz. difference in weight. He had to give up some features and some warmth, and he wanted those features and that warmth. His conclusion was that the new parka was overhyped and a poor value.
Undoubtedly, Jim, for you that new parka is a poor value. It doesn't fill your need. You should return it. Don't stew about it. Rectify the situation. Buy a parka that is warm enough and has the right features for you. But for someone else whose situation and needs are different, that parka might be perfection itself.
As others have said, and you too have often said, it's all about matching the gear to the mission. This gear is just a mismatch you hoped would turn out better than it did.