I would not hold my breath, but that very well could (in theory) be roughly the shape of things eventually to come.Just wait for that mythical Final Edition, where everyone gets exactly the rules they want because they choose which rules they want for their own games, still professionally designed, rather than relying on an immutable codex of rules that happens to change once every 5 or so years.![]()
Recall that the first two D&D supplements were titled Greyhawk and Blackmoor, after the first two campaigns. They were in essence presentations of "house rules" (although mostly from the pens of Gygax and his crew even in the booklet attributed to Arneson). In other words, they were not in a sense any more "core" D&D than The Arduin Grimoire.
The concept of the game as singular and more or less consistent entity, beyond an identity that was to some extent defined in opposition to identification with any particular source of inspiration, started IMO really to get solidified with AD&D (and the several Basic sets that for so many preceded the hardbound tomes).
The notion that "everything (published by Company X) is core" has played ever more hob with the original tool-kit concept as the product has tended to a more monolithic kernel (to borrow computer operating-system jargon). Inherent modularity has given way to large-scale integration, and the "basic" game has grown into a monster.