I don't see what the business case for a metaplot returning would be: any value added seems minimal, whereas it would actively alienate people setting their game in another timeframe. I doubt the current approach to RPG timelines will change, even if other elements get changed.
The fact of the mater is, presence of meta-plot and a living timelined campaign setting (or multiple settings), is a pure mater of personal taste. My view is that the the divide is 33/33/33.
-1/3rd HATE setting meta-plot, they tend to say things like "This robs us of agency, it's railroading the game on the highest level, it can really screw characters in living campaigns (Divine caster who's god dies)". They consider it ESPECIALLY EGREGIOUS when tie in novels effect the setting meta plot. These players tend to vomit blood when someone nearby mentions Dragonlance.
-1/3rd LOVE setting meta-plot, they tend to say things like "It keeps the setting fresh, by running these adventures players get to be involved in events that shape the campaign world, it really gives the campaign a sense of continuity". They either don't care, or actively enjoy that Tie in Novels (which they read voraciously) affecting the Meta-Plot. These players tend to say "When oh when are they finally going to release a Dragonlance setting book for the current edition".
-1/3rd either don't care, or if they do have an opinion either way, it's not strong enough to matter beyond a general "I prefer [blank] but whatever"
So, at least in my opinion, the presence of a Meta-Plot and a continually advancing timeline in the game setting has NO business effect either for OR against. Business and sales lost on one side of the equation are made up by gains on the other side, and when the pendulum swings the other way, business and sales lost on the other side are made up by gains on the first.
Therefore, the presence of "Meta-plot" and "Enforced Timeline" within the game line is really a matter of the preference of the game design leads. Hasbro has a history of doing random shake-ups, particularly of cleaning house in a division around line changes like game editions or toy line changes. So, IF, when they decide it's time for 6e, they put someone in-charge of D&D who likes meta-plot and firm timelines, that's what 6e will have. And if not, then not.
TLDR: It's not a business consideration, it's purely the taste of game-line heads.