Why D&D has nothing to do with the original sword & sorcery stories

Old school D&D: “I’m modeled after the old science fiction stories, where life is short and unforgiving. Your character probably dies very early on. What would you expect, with those ridiculously low hit points?”

Old science fiction stories (Vance, Leiber, ERB, de Camp, Carter, etc): “Our protagonists are heroes, that’s why we’re still (or, again) so popular with many readers. Life is short and unforgiving – but not for our heroes; to them, it’s dangerous, but they usually live to tell the tale.”
Notice anything? Old D&D was definitely not “modeled after” these stories. Anybody seriously claiming D&D is sword&sorcery in the tradition of Leiber, Vance, and their companions is wrong. The low survival rate of early D&D is a remnant of wargaming and has nothing to do whatsoever with the literary sources.
Even the term “Vancian magic” in the context of D&D is completely incorrect. Reading the literary source material, you’ll soon find that Mazirian, one of Vance’s heroes and a very powerful sorcerer, for instance tells the reader that he can hold four of the best/most powerful spells at any one time in his memory, or five minor ones – at best.
There are only 100 known spells on earth. One hundred. And every mage is a potential target because he might possess a spell that others don’t. I think cozy evenings in the armchair, while smoking a pipe, are definitely not on the list of those guys.
In my proto-D&D games, I’ll change all of this to make it real Vancian. What do y’all think?