WotC just dismisses it and waves their hands. They just expect each individual table to decide or they just retcon it. WotC did try to explain the transition from 3.5e to 4e and back to 5e with a bunch of catastrophes to the world but again, it wasn’t implemented for moving the story. It was to change the gameplay.
4e was a fairly radical change to D&D as a game system and it seemed to model itself more to video games and MMOs. If it was a success, it would have translated very well to computer games. WotC incorporated a big change in Faerun at the time to match the gameplay and a lot of players hated it.
So they kinda backtracked with 5e, including the setting. 100 years have passed but it’s pretty much the same vibe as the 3.5e era.
I mentioned superheroes because that’s the trend I’m seeing in entertainment. I think Larian is following that trend. I call them the Michael Bay of video game developers because of it. They like flash. They like big dramatic scenes and explosions. They don’t seem to care if it really makes any sense in the setting.
5e is more grounded to earth than they like so they went with DOS system and added 5e rules on top of it.
Being near the end of a long running 4e campaign and have played a lot of 5e, there are actually a lot of changes from 4e that carried over into 5e I felt. While they are two very very different systems with wildly different strengths and weaknesses, there still feels like a throughline from 3 to 4 to 5 and every system could be enjoyed. That said, 4e genuinely would have been a lot easier to adapt into a video game. Abilities in 4e were designed with combat first and roleplay second, many could be applied to RP interactions but a player had to figure that out themself. 5e designs so many spells and abilities with RP first and combat second, most are still combat focused but a lot of abilities are designed with out of combat utility and roleplaying in mind. For example Speak With Dead which to become a focus for Larian cause now they had to voice and write lines for dead people. Also 4e gave you big stuff earlier I felt, or at least it did for the wizard. At first level I could summon a Fire Warrior or Dretch to fight my enemies and wreck havok, or burn down a building for a stupid entrance. 5e, a first level wizard is less... grand, the first level spells are useful but barely any would fit Larian's brand of big explosions and epic creatures, and even to level 4 things are toned back. That is cause 5e is considerably scaled back at early levels. But it does get to Larian's levels of grandness at later levels so I think they should try to be a lot closer to 5e and have that patience so it has more meaning when we reach those higher levels with large explosive abilities. Basing things on DOS and adding 5e on top ends up doing a disservice to both Larian's explosive style and 5e's system, when sticking to 5e would actually highlight both is something I believe.