I am a big fan of the work James Maliszewski does over at Grognardia. After his Dwimmermount campaign, I suspect his next biggest legacy will be is classification of the history of the D&D hobby into various "ages."
For me, the interesting bit is where to draw the line between the Golden Age and the Silver Age. Which is another way of saying, when did TSR turn up the suck knob on this hobby? And who is to blame?
One obvious fracture in the history of TSR is the ouster of E. Gary Gygax at the end of 1985. TSR products took on a very different sheen after that; a sheen I did not ken to.
A lot of blame of the suckage gets dumped on Dragonlance, the work of Tracy and Laura Hickman. Certainly, I thought that series was unctuous and boring. However, I enjoyed the heck out of the Desert of Desolation series, which apparently is not universally loved. Heck, I think the original Ravenloft module is entertaining (if not exactly what I would want from a Vampire module).
Dungeon hacking is fun, but it does get old. Give the Hickmans some credit for trying some new.
Being older and having seen real companies grow and change. Leadership really does matter, as Apple is about to find out (and Microsoft has already learned after a decade of failure from Balmer).
So if the Hickmans rose in ascendance at TSR, might Gygax be to blame? After all, that dude was busy in the early eighties. He was spinning up various media deals and spending a lot of time in California. There is little question that Gygax was a real content producer and visionary in the 70s, but perhaps he was grooming others to take on that mantle.
Certainly, later Gygax products for TSR were mediocre. Unearthed Arcana should have been called The Best of Dragon, IV. Oriental Adventures was unfinished as a system and felt more like fan-fiction. And he pretty much farmed out the completion of the Temple of Elemental Evil to poor Mentzer (you might not like the product but at least he got something published). Any wonder why the Blume brothers might have been looking for a replacement for Gygax and a content visionary?
One last point I would make is terms like "golden age" are always misleading, tinged with nostalgia, and willfully forget the terrible bits of the time. 1975-1983 was a crazy time for a hobby trying to define itself. Great things certainly were produced during that time (a time when frankly adults seemed to have read a lot more pulp fiction than they do now). When I look back at that time, I can't but see the Zeitgeist of the times. Despite the paranoia and disillusionment engendered by Watergate, there was still a lot of optimism in this country that is absent today. That's why radically dystopian games like Gamma World and Paranoia could still have a light sense of humor.
Mostly, what was good about the Golden Age was that no one knew what D&D should be. This allowed for a lot of influences on the game that would later be filtered out.
I realize that as hobbists, we owe a lot to Gygax, Arneson, and company. But as adults, we can be more critical and honest with ourselves. Luckily, D&D has been "open sourced." We can make of the hobby what we will.