I'm still a little bit sore over the "Basic" vs. "Advanced" versions.
The best thing to happen to the hobby, in my opinion, was the Open Gaming License. This was more than just a game...it was a toolbox that gamers could use to build the exact game they wanted to play...and build it in a uniform and standardized way. If a product had the D20 Logo on it, you knew that it would work in your game. And the D20 Logo was
everywhere in the mid-2000s. Forgotten Realms D20, Ravenloft D20, Oriental Adventures D20...it was like a high school class reunion for the "old guard," and things like Eberron and Ghostwalk were bringing new gamers to the hobby in droves.
When 4th Edition was announced, all of that changed. Third-party publishers shelved their projects, waiting for word on the new edition and whether or not it would also have an Open Gaming License toolbox for them to use. Only Pathfinder and a tiny handful of others kept printing under the current license...a decision that would make them very, very wealthy. Then 4th Edition was released--and it didn't come with a toolbox.
4th Edition didn't "kill D&D" as some people proclaimed. But Hasbro certainly tried to kill the OGL, and the way that D&D material was being produced at the time. I remember reading dozens of articles, game blogs, and commentaries about the legality of the OGL, and the struggle from Hasbro to reign in the booming third-party industry, and their ultimate decision to restrict the license for 4th Edition. It was a dark time. Some bridges got burned. Talented people lost their jobs. A lot of publishers walked away.
Fortunately for gamers like me, the OGL survived....thrived even, largely due to the hard work, creativity, and old-fashioned good luck of Paizo. Which is awesome, because we will never see anything like it ever again in this hobby.
So when people talk about a "Golden Age" of D&D, I don't think about high school and the Moldvay Basic/Expert rules and the Isle of Dread, even though they were the best gaming experiences of my life. Instead, I think about the Open Gaming License and how it saved our hobby from fading away forever after TSR went under.