This was very true for 4E, but based upon the direction of 5E they realized that was a mistake for the brand.Your last sentence catches why they can't do this.
The mechanics need to support the setting. And to a lesser degree, the setting needs to support the mechanics.
For example, straight D&D 5e doesn't strongly support a Middle Earth type setting, because of the high levels of magic and such. You'd want to either adjust the rules (like has been done in 3rd party suppliments for ME) or adjust the setting to jive with the rules.
What this means is that when there are significant changes to how the mechanics work, they need to update the setting to be in sync. And since lore is often linked to setting, those can need to be adjusted as well...
This was very true for 4E, but based upon the direction of 5E they realized that was a mistake for the brand.
However, in 5E I've seen the following games run:
* FR set at the time of the original boxed set, using a 2nd edition module (Haunted Halls of Eveningstar).
* Original Dragonlance Saga
* Shackled City
* Dark Sun (original adventure path)
* A Middle Earth game (PCs had to have more levels in Fighter, Monk or Rogue combined than any other class - worked well)
* A1 to A4
* G1 to G3
* Gamma World
* The Sunless Citadel Adventure Path (SC, FoF, SiD, SS, HNfS, DH, LotIF, BBS)
* A Planescape Game
* Ravenloft
5E adapts very well to prior edition materials. As long as they don't rebuild the entire game like they did in 4E, they could take my suggested approach... and to be honest, I did run a FR original boxed set era game in 4E, but did not enjoy it as much as I could have...
Going down my list:If you've seen all those without rules changes to support the individual settings, then you're missing out. Some will play base 5e just fine, but others like Dark Sun played base 5e rules with cleric, no psionics, no muls or half-giants, no despoiling - that's not Dark Sun. Same for Dragonlance, Eberron, Ravenloft, etc.
It depends upon how you define Lore. For example, There are Wikis that do exactly what I propose out there - they're just not maintained by WotC.If you have played with alternate rules for them, then you see how setting fluff/lore/feel and mechanics are intertwined, and you can't publish "books of lore, good for all editions" and assume that they actually will fit all editions.
I don't get what the lie would be, and as for it having limiting facets on future editions - Not if the editions have as much in common as AD&D, 2E, 3E and 5E. Seriously: Name one thing from AD&D to 3.5 that is not easily translated to 5EIf you do that, you're either lying on your product or chaining yourself for future editions.
AD&D, 2E, 3E and 5E all translate - lore wise - easily. As stated, I've seen all of the above work well.Look, I've got boxed sets of FR lore back from AD&D 2nd and Myth Drannor and the like. They didn't translate nicely to 3.0, and same for 5e. While 3.0/3.5 to 5e isn't bad for how lore feel fits into mechanics, that's not always true between editions.
One thing I wish is the players handbook listed the spells like the 1e version did: by class, then level, then A-Z. It's next to impossible to scan the spells when choosing

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.