Not in compatibility, but the old guard of websites and portals controlling access to games is completely gone - nobody cares what the dominant gaming press, YouTube, or hub sites think anymore. The whisper networks are exposed. Site bans for creators are flying, and those who had control are losing it - and their minds. Even some YouTube creators slowly lose their grip on reality as the scaffolding of 'what once was'' buckles, folds, and comes down in a crash.
The zeitgeist is dead.
Let's go pre-2022. You made an adventure or supplement for the top OSR system (Old School Essentials) or D&D 5E a few years ago. There was no question you did.
Then the OGL was killed.
The ground was no longer stable anymore. 5E blew up, and many left for Pathfinder 2. Many of the 5E community split off, and we have Shadowdark and Tales of the Valiant. And we are seeing that in the OSR, with the 4th generation OSR games just doing their own damn thing and throwing the middle finger to anyone who thinks otherwise.
Shadowdark is a good example. A group of amazing creators found they had more fun with OSR games than they did 5E, so they set out to build a 5E-like system that simulated old-school sensibilities. Shadowdark is the gateway drug for the OSR, and I welcome this game into our community with open arms - since this helps a vast group of players only used to 5E discover the joy of a hardcore 'Dark Souls' style dungeon experience that D&D refuses to supply.
Dragonslayer goes hard on the old-school, with a refined mix of B/X and 1st Edition. There is even artistic nudity - just like AD&D, don't complain - in this book, and the creator speaks openly about what he likes and criticizes the direction of many newer games. He takes flak, and nobody cares. The game slaps me back awake like it was the 1980s again, and roleplaying was something only the cool college kids did, and I wanted in on it.
Since this also is the game for all the fantastic mega-dungeons: Barrowmaze, Highfell, and the others - with a new one coming this year, this one game and those dungeons can provide 20+ years of play without needing to buy anything else. This is expensive, but a 300-page book packed wall-to-wall with consistent OSR art and sensibilities is like a rallying call to me.
It is worth the money. This isn't "just another B/X."
It is B/X+.
The classes in DS are fun, especially compared to OSE or Labyrinth Lord. Fighters are worlds better in DS, since they get a cleave ability when they kill any target at level 1, getting an extra attack, plus another every 2 character levels. So, if you kill an orc at level 1, you can immediately attack another. At level 3, this improves to two attacks after a kill, and at level 5, that is three attacks - and this applies to both melee and missile weapon attacks. This has no HD limitations.
Clerics get a divine channeling power that lets them swap a 1st level spell to cure light wounds, and mages get that but for detecting or reading magic. These are "fun changes," I bet a little inspired by 5E, but it gives casters better-prepared spell choices and keeps them flexible. Some of the pain points of B/X have been house-ruled away and made official rules.
Thief percentages are not horrible; they get a d6 hit die, and a failure margin built into the pickpocket skill could be extended to other skills for fun. They can also appraise treasure. The rules also say, "roleplay precedes thief skill die rolling," - which means in many cases, with solid roleplay, YOU DO NOT HAVE TO ROLL. If you care to creep behind a low wall, out of sight, the referee can rule - it just succeeds, good plan. No game has a "roleplay trigger" for thieves, which makes playing them incredibly fun and interactive as you try to think up strategies to avoid rolling.
Using a rope and spikes, no roll is needed for climbing. If you studied the key, no roll is needed for lockpicking. If you recently disarmed the same exact type of trap, no roll is needed to remove this trap. If you have a good hiding spot, no roll is needed to hide in shadows. If you drop your pack, have a quiet approach, and just creep up with a dagger, no roll is needed to move silently. If you watch your target and know which pocket a wallet is in, and have someone distract them, no roll is needed to pickpockets.
Ninja roleplaying is back with the DS thief class, which is excellent.
I feel like my eyes are open.
OSE. 5E, and Labyrinth Lord don't do this, and their classes feel very "one note" without tools that can provide fun opportunities at the table and player options. If someone asked me to play a fighter, cleric, mage, or thief, I would choose DS over OSE, LL, or Shadowdark.
I get the same feeling 5E gives me - I have the tools to deal with situations. However, here, roleplay and creativity matter a lot more.
Dragonslayer is the next B/X standard bearer. They took the unfun parts of B/X away, or parts where you sit and feel "I am stuck doing nothing," and gave characters options and tools. And these changes have been tested over the years at the mega-dungeons mentioned above, so they are proven winners.
And I get the feeling DS is closer to a Shadowdark than B/X, at least in the design philosophy of "making the game fun" coming before "making the gameplay just like the old one."
And it isn't a digest-sized book, which I see as a positive. Small books never stay open, the information-to-page ratio is horrible, they go on hundreds of pages, and their type, for my older eyes, is a pain to read. Give me a full-sized book with excellent art and page layout any day.
Another amazing Kickstarter late last year, and shipping this year, is the B/X-inspired ACKS 2. This did better than his previous Kickstarters by 3-5 times, and he rewrote the game to eliminate the OGL. All the monsters and spells have been reimagined to fit the world he wants to see, not a world where B/X is forced in there.
Another game that wrote the OGL and SRD out of existence? Basic Fantasy 4th Edition.
A game that went Creative Commons? Swords & Wizardry.
You can't compete with Wizards of the Coast! They are like [throw some considerable number here]! Well, Kobold Press thinks they can, and for that matter, Paizo is doing an excellent job. We are getting a complete replacement for all core books, compatible with 10 years of 5E books - and that is a wonderful thing because people's libraries and investments are being protected.
Add Level Up Advanced 5E to the list of games throwing the middle finger at common wisdom, though they were three years ahead of the curve. This is a complete rewrite of the SRD, with no licensed language, and is free from any OGL license mess. This game is still strong and is another favorite of mine that mixes old-school design with 5E.
But we are seeing a crumbling narrative and a death of the gatekeeper sites and zeitgeist. Wizards killing the OGL killed these cliques' control and the feeling you needed to "play along" to "play at all." If they are unfun, the old ways of doing things get tossed in the bin. Nobody feels beholden to exact copies or Xeroxing games anymore. If a part of a game sucked in the old days, why do we have to replicate it?
And the games coming out in this period, especially the 4th generation OSR games, are fantastic.