Well the point of this thread was to quibble to death over whether the 80s were "a" or "the" Golden Age--that was the point of the inquiry.
It isn't well-defined nor should it be. I fully understand and embrace that it is a subjective term with many possible meanings. But Wikipedia has a nice entry right here.
Based upon the mythological perspective, I'd have to call the '74-80ish era the Golden Age of D&D and RPGs in general (see post #18 in this thread). But I don't necessarily mean "best", but in terms of myth the Golden Age represents the first time, the period in which men were closest to the gods, with the initial inspiration and experience of life; generally there was little or no suffering in the Golden Age and life existed with a sense of timeless stability. And it invariably ends with a Fall.
But perhaps the most important aspect is that it is "lost"--and there is a sense of sadness, or at least nostalgia. It was, in a way, a perfect time--but simpler, and thus not necessarily as full as a later age. This correlates with RPGs quite well, I think, in that there was probably a great sense of excitement and growth in the 70s, but they didn't have the wealth of RPGs that we have now, nor the ease by which they are produced.
Most mythic traditions hold that the ages are cyclical, that the Golden Age comes around. There are probably numerous micro-cycles as well (e.g. the four ages within a given edition).
A good summary - I think the only other thing that you could add is the transition from actual game system to icon status correlates to the lack of interest from the publisher.