Hmm...interesting perspective. You may be right that Moore's too reverential of the 60s stories, but then I am too, so it doesn't bother me so much.
I love Superman in the sixties too. This is why this topic is such a thorny one for me: 1) I do love the period Moore likes and I feel somewhat guilty attacking him for using elements from a period I enjoy, 2) Moore as a writer can write about whatever he wants, and 3) I really do like Moore as a writer (mostly - which is what this thread is about, anyway).
Essentially my problem with Moore is, he is elevating a period of the character of Superman that was in many ways, very atypical...as being the entirety of who Superman is, both in his true-blue Superman stories and in Supreme, and that strikes me as being dishonest.
The point of that story was to provide a coda to the whole pre-Crisis mythos and like it or not, almost everything of any lasting importance to that mythos came from the Weisinger era.
For the sake of argument let's say that statement is true (though I'd dispute it - so much of the Weisenger era stayed in the Weisenger era, and furthermore there's a difference between great ideas and not knowing when there's too much of a good thing).
If Alan Moore wanted to do as you say and bring to a close things of lasting importance to the mythos, instead of an exercise in sixties fetishization like I say... why the hell would he make the Kryptonite Man such a big player?
This also doesn't account for why Moore used the Legion of Super-Villains as they were in their first appearance instead of any of the subsequent rosters. Hey, he didn't even use any piece of LSV characterization post-sixties: like for instance, the fact that Saturn Queen was one of Prince Evilo's ex-wives. It is THAT that is unprofessional and regressive.
If Moore wants to use the LSV as they were in their first appearance, bully for him, I say. In fact, considering the LSV's time travel powers, their Silver Age-era characterization may be the only truly regressive element that truly makes sense. The LSV can pop to the end of Superman's battle anytime, maybe even after that fake kangaroo court the villains hold for him. But combine that original roster of the LSV with appearances by Silver Age Legionnaires (what, he couldn't get permission from Levitz to use Wildfire and Blok or something?) and Jimmy Olsen being Elastic Lad and you get something that disses by omission.
I honestly want to sit Moore down with some Len Wein tales with Chemo, or that Cary Bates story where Superman fights Weather Wizard, and say, "Look, you limey beardo, just read these. And if you don't like them...I promise, I'll get ketchup and eat them right in front of you."
The 70s gave us the elimination of Kryptonite (soon reversed), the dimunition of powers (quickly ignored), Clark's move to TV (a pretty cosmetic change, and one reflected in the story anyway) and not a whole heck of a lot else.
This exact same argument could be made of the Weisenger period as well. In fact, much more of the Weisenger Age stayed in the Weisenger Age, than Schwartz-era stuff stayed in the Schwartz era. Some of the stuff Uncle Morty and his boys threw out stuck (different colored Kryptonite, Kandor, Brainiac) but an overwhelming amount of it didn't and just was never mentioned after a certain point: when was the last time anyone used the Phanty-Cats after 1970, for instance? Zha-Vam? The Flame Dragon? Hercules and Sampson? Mynah the Super-Bird? The Kryptoniad? The Jimmy Olsen Fan Club? King Krypton? The duplicate world of Krypton filled with robots? The asteroid that resembles Lara and Jor-El? Lois and Lana getting powers? Jimmy Olsen transforming in a non-ironic way?
Julie Schwartz may have downplayed a lot of the Weisinger era baggage, but it didn't eliminate it. Kandor, Krypto, the Zone, etc were all there, always waiting to be used in some way should the need arise. So when Moore set out to "wrap up" the mythos, he was bound to bring up that stuff that happened to be invented in the 60s, because that was the stuff that mattered, the stuff that was still around and in play and unresolved.
Moore brought in sixties stuff for his stories because Moore loves the sixties.
I'd agree with you here if not for the fact that Moore really DIDN'T resolve the plot elements that mattered with his "Whatever Happened..." He didn't talk about Kandor or the Phantom Zone. He gave closure to the story of the Kryptonite Man, Elastic Lad, and Lana Lang getting powers - in other words, the epitome of jettisoned Weisenger baggage, instead of a lot of the stuff that Uncle Morty brought in that stuck, like the Phantom Zone.
Incidentally, if you read that "Tomorrow Stories" issue where the First American fights Dozier D. Daze, the evil nostalgist, and then read his SUPREME - the bitter, unintentional irony becomes almost physically painful.