My comment got far too long, so I turned it into a blog post.
First off, I think it’s pretty apt that he uses many of the same terms used to describe comic book eras. Golden Age, Silver Age, Bronze Age.
It can easily be argued that Golden Age comics were, perhaps, more pure, more original, and probably a bit more naive. But it’s nearly impossible to argue that it (or Silver, Bronze, whatever) was objectively better than any other age.
I find that fitting.
And did anyone else notice that, if you extend past the Dark Ages era (late 2e, according to James) to 3e, historically you would hit the Renaissance?
I find this apt, too. See, the renaissance was a time of cultural change, after all. Things got better (than the Dark Ages, debatable for previous ages), particularly from a cultural viewpoint, but culture and society changed drastically. While they resemble the previous ages much more than the Dark Ages, they were still very, very different.
Again, seems fitting.
The Reformation fits well for 3.5e.
Age of Discovery/Exploration (which overlapped the Renaissance) can be used for the era following the Eberron campaign setting, as WotC explores new mechanics and options (Tome of Magic/Battle for big examples, and the Eberron setting itself), braving new waters with some drastic changes from what has come before.
And to continue the trend, 4e corresponds fairly well to the Age of Reason/Enlightenment. During this age, much of philosophy moved towards a mathematical and deductive basis. This didn’t sit right with some people, who demanded empirical evidence, and debates on which philosophy was “correct” raged. (Pathfinder could be seen as the empiricist movement, perhaps.) 4e, as well, moved away from empiricism (simulation) towards mathematically balanced gameplay.
…huh. That worked… surprisingly well.
Now I’m waiting for the Industrial Revolution. C’mon, 4e d20 Modern!