I've been running D&D as an adult, nonstop, for around 30 years, and playing since I was a kid. Back then "D&D" meant anything we could get our hands on. My first set was the 1977 Holmes Basic box, a Christmas gift from my aunt. At that point, D&D was being featured in the mass media, so it wasn't some counter culture gift decision.
The AD&D hardcovers followed soon after, and we devoured and memorized them, mostly because it's all we had to read at the time. As we collected various game books as we could find them, we made little distinction between Basic and AD&D, other than assuming Basic must be for inexperienced players. The Holmes box really was an on-ramp to AD&D, so we weren't entirely wrong, but Basic later grew into its own complete game, all the way to name level and beyond, and we missed that at the time. We blended the two together constantly, and there was a ridiculous amount of product to blend. Through 2000 I'd estimate something like two releases a month.
After high school I ran Oriental Adventures in college, then fell in love with Planescape and moved to AD&D 2nd Edition. Like the Basic versus AD&D thing, I mixed 2nd edition with 1st without much thought.
I swore I would never leave the AD&D universe. I was one of those people who declared they already had everything they'd ever need, so why change. Planescape was the first time I had become a "completist" collector, including hunting down things like promotional convention posters. This was the era of Ebay.
Then 3rd edition came out, resolved many of AD&D's problems, and I jumped on it and never looked back, at least not until recently. We played 3.0 through 3.5 to the bitter end, then dabbled in 4th edition, which I liked but the players despised. I like to say 4th edition is D&D for people who don't like D&D. 4th made running a game a breeze, while the characters felt soulless. 4E gave way to Pathfinder 1E for us, which we happily played for years, until 5th edition came out and we embraced that too. I played in a Pathfinder 2E game and loved it as a player, but it looked daunting to run. We ran a campaign of 5.5, where the rules changes seemed unnecessary, and then I got the itch to run a megadungeon. For that, I looked back to Basic.
Why go old school
The question I get is why switch to an old school game at all. The game I embraced was Old School Essentials Advanced, a blend of Basic D&D with some nods, not quite enough if you ask me, to AD&D.
Put simply, as editions progressed they aimed to fix problems that many of us now recognize as features. Lethality is one. Resource management is another. Dungeon crawls are about counting torches and losing characters. You don't camp in the dungeon. You get in, do your business, and get the hell out before it closes in around you. That fear is not present in the modern game, and what I learned is that the "bug" gets fixed everywhere beyond the Basic framework, including in the AD&D versions.
A tool for the job
So what we have is a specific tool for a particular job. Basic D&D does granular dungeon adventures very well. What it doesn't do well is offer character options. My players were somewhat unhappy with what their characters could do. But the point of a Basic game is that the main character is the dungeon, not you. You don't need to get too tied up in character options when your character's lifespan isn't terribly long.
When I started a new campaign, I decided to offer more character options and to tell a story. We moved to OSRIC, an AD&D clone, which felt like coming full circle in my gaming career. The game became more story driven, and OSRIC allowed for more survivability. Characters were more powerful, the granularity of resource tracking was lessened, partly because of the system and partly because we weren't dungeon crawling anymore. Suddenly the tool metaphor clicked. If I wanted to tell a story, the last thing I wanted was a bunch of dead story elements scattered across the world. I wanted survivability. I wanted to move the story along, not go back to town to hire torch bearers. OSRIC let me blend a bit of OSE granularity with a story game, though I asked myself several times: if I'm going story, why not just use 5E? The players would certainly prefer it.
Pick the tool that fits
I've come to the conclusion that these editions are all ripe for use, depending on what you want to do. It would be foolish to get attached to just one.
If I want to run a dungeon crawl, OSE or something similar is a requirement. It should feel gritty and dangerous. You should be afraid. We did that running the first six levels of Stonehell, before I frankly lost interest in the grind. If you want to run a story game, a real campaign with a theme and invested characters, you want heroic characters and survivability. AD&D (OSRIC) will suffice, but I think 5E would be the preferred system for players. You'll also have a much easier time recruiting players for the latest edition than for something older.
One player asked why I couldn't just make my current OSRIC campaign 5E. That's an example of not understanding the infrastructure under the campaign: the re-skinned dungeons, many of them famous, many of them completely rewritten because they don't match modern sensibilities. I could certainly tell my story in 5E, and might in the future, but my main joy in running an old school game is discovering so much nostalgic content.
Cherry-picking 35 years
My current OSRIC game mixes OSE, OSR, Basic, AD&D, AD&D 2nd Edition, and even Adventurer Conqueror King adventures as if they're the same game. That means I get to cherry pick the best of maybe 30 to 35 years of content. None of this cherry-picking would even be possible without the Open Game License, the 2000 document that let publishers reprint and clone the old rules. OSRIC, OSE, and Adventurer Conqueror King are all children of the OGL. I get to run classic AD&D adventures like Lost Caverns of Tsojcanth while also discovering gems from Basic that we missed or overlooked, like the absolutely bonkers Night's Dark Terror. We started with Sinister Stone of Sakkara, an Adventurer Conqueror King adventure, followed by an OSE sewer crawl, a sojourn into Night's Dark Terror, then another OSE, then a couple of OSR, then AD&D, and so on, without any concern for compatibility. What stayed stable was the desire to keep the story moving forward and to treat the players as the main characters, rather than the campaign.
And because of that, I think 5E is likely better for that job. I'm not really sure the AD&D era did much for the DM, even if the players liked it more. I believe each era of D&D was attempting to fix an undefined problem, chasing a feeling, a desire to make characters more real, while creating more tools to tell stories. Fourth edition is the exception that proves it. Whatever I think of it at the table, it knew exactly what it was fixing: the DM's prep load and the math of a balanced encounter.
In 4E, I could take a cool, low level adventure and in an hour, scale it to a high level adventure. You can't do that in any other edition. It answered a defined problem while the rest chased an undefined one, which may be why it feels so unlike the others. D&D is really two games, in my DM's mind: the deadly, granular dungeon crawl and the heroic, story driven campaign. Various editions are exploring a tension between the two, rather than some aim at perfection.
