DS is too different and unique, too far from the rest of generic systems. We shouldn't be too surprised if Paramount wanted to produce a miniserie for the streaming service.
When you say certain title is for mature audience, some underage wish it more. There is a lot of children playing "Call of Duty", for example.
Maybe WotC could create a special label within DMGuild. I suspect this could be the main reason, WotC fears the toxic creators.
Other option could be to publish a sourcebook for a charitable cause. It wouldn't be the first time, would it?
I think the most reliable option is the update of the crunch, and lore/background about the Athaspace but without many details about the Tablelands. The metaplot would appear in other transmedia titles. Then we would see "Athaspace" unlocked in DMGuild, but not the original Tablelands. A spin-off? It is possible, about defilers traveling to other zones within the Athaspace.
Or a "spiritual succesor", in the sense of a new setting "almost from zero" about "hell of earth" where the world is a demiplane created when a planet and a region from the infernal planes were almost merged by fault of some dark ritual. Then the sorcerer-kings are "hell-lords", but their domains are used as mixture of "firewall" in the space-time continium and "recycle bin", suffering failed attempts of planar invasions by horrors as the sheens (biomechanical abominations) and creatures from the Far Realm.
* Other of the main handicaps for DS is the limit of options. The "crunch" is not wellcome but if this is from sourcebooks created specifically for this setting. Then we have got troubles with players who want to add their special touch in their game, for example monks fighting in the gladiator arena, or paladins working as templars. This is worse if we talk about new classes or PC species. Then here the spin-off in other zone of the Athaspace should be a better option.