Compare that to a game like Magic: the Gathering where the rules have evolved greatly since its inception but every card in the game is still playable (barring some exceptions) and you can play a deck using only 1994 cards against a deck made of only 2023 cards and the game accommodate both. (Balance issues notwithstanding). New sets are effectively additive*, whereas new editions of D&D are replacing older ones. (* Magic, of course, has formats that range from rotating [old cards leave, new cards enter] and eternal [all cards within a threshold are playable]. YMMV depending on your format. Playing standard requires constant replacement, while playing Commander is purely additive)
Is there a way D&D could have been made additive rather than replacing itself every edition? I guess that's what 2024 is opting for. Or is RPGs one of those things that benefit from a good reset ever so often?
This got me thinking. If you wanted to adapt the Magic model to D&D, with continual innovation but maintaining the structure, you should probably look to the other thing Magic does: shift setting.
Magic sets shift from plane to plane, and changes the things that are available. Some things are constant, while others change, or at least take different tacks on the same concepts. The most pure expression of this would probably have been the Jakandor setting from late 2e, with the expectation that you'd do another similar-sized thing each year (or maybe every other year).
For those who don't know, Jakandor was a setting that had three books done for it: Jakandor, Island of War; Jakandor, Isle of Destiny; and Jakandor, Land of Legend. The setting was an island – I think roughly Great Britain-sized, but I could be misremembering that – with a primary conflict that was summed up as "barbarians vs wizards." The island was home to two different cultures, one emphasizing spirituality and martial prowess and the other magic and rediscovering lost lore. One of the books focused on the "barbarians", another the "wizards", and the third had some lore unknown to either side plus a bunch of adventure seeds. Each of the cultures had a number of "kits" specific to it – basically what 5e would call subclasses. It was a pretty cool setting, but definitely didn't have the depth of something like the Realms or Dark Sun. But I could totally see them doing something like that each year, or every few years, to provide something for those of us who like new things without resetting everything at the same time.
I think the closest we get to something like that in the modern era are Paizo's adventure paths, each (more or less) of which is set in a new location and has a different focus. But they're generally more permissive than what I'm thinking of, and generally relies more on very mild suggestions regarding external material than actual reshaping. The Player's Guides provide some nudges regarding useful choices but generally won't have any restrictions in them.
Which is interesting, because I'd argue the opposite. The last few years of 3.5 were when the bulk of the best material was published, I feel.
I don't think it's a given that publishing quality will decline over a longer length of the production line.
Generally speaking, two things will increase the longer an edition goes on. One is the system mastery of its designers. They will learn what kinds of things work and what doesn't, and what unintended things are going on with the game system and how to either embrace them or counter them. So the technical level of later products will generally be better than that of earlier products. The other is the level of experimentation. The low-hanging fruit is done first. Start with the basics in the core books, then expand to known concepts that didn't fit in, and then you start getting weird. The 3.5e monster books were good examples of both: the MM monsters had the old standbys (ten dragons, six giants, a bunch of demons and devils, orcs, gnolls, kobolds, goblinoids, etc.) but they generally weren't all that well designed, while later MMs had monsters that were better mechanical designs but attached to weirder concepts because all the classic concepts were used up.
When it comes to rules expansions, being experimental can be both good and bad. Sometimes you get awesome things like the Book of Nine Swords. Other times you get Incarnum, which was weird enough that players generally didn't bother with it and designers didn't have anything to properly balance it against.
