Kirby gained prominence over every decade from the 1940's to the 1970's because the books he created consistently sold well. His work was so widely imitated that he changed his style in the late 1950's. Kirby was not a Spice Girl, he was the artist that the Spice Girls of comics imitated!
At Marvel in the 1960's, Kirby's was the "house look" that every other artist had to follow. And 50 years later, most of the characters and designs for them are still the Marvel standard. That's not even getting into his Fourth World, KAMANDI, THE DEMON, OMAC and so forth, that are likewise enduring hot properties, both in comics and in other licensing.
I don't think Kirby is a fine artist the way Neal Adams or Berni Wrightson or Frazetta or Williamson are. But Kirby is a very skilled storyteller and comic book artist. I respect that you and others may not like his particular style. But the same way I see artists like Will Eisner, Berni Krigstein or Jim Lee, whose style I don't particularly care for, I can still see why they are well received by others, even though their work doesn't particularly appeal to me personally.
If you want to see some great Wrightson art, pick up SWAMP THING: DARK GENESIS or one of the other reprint versions of the Wein/Wrightson SWAMP THING 1-10. And his BERNI WRIGHTSON: MASTER OF THE MACABRE 1-3 (1983, Pacific, reprinting his very best Warren magazine work in an outstanding color version.)
I also have an affection for Aparo, Swan/Anderson, Dillin, Novick, Kubert, Kaluta, Aragones, Thorne, Ditko, Morrow, Nino, Redondo, Dezuniga, Grell, Rogers, Golden and many others. All great in their own modest way. And I don't put Kirby above them, except in the sheer quantity of memorable work he produced. And the contracts awarded to him by both Marvel and DC certainly attest to his own personal achievement in the field.
The DC work by many artists from 1968-1975 or so represents some of the best work ever done, and (as COMIC BOOK ARTIST editor John B. Cooke said) is arguably the true Golden Age of comics.
