This I think is part of your admiration of 4e rather than an objective fact. In my own subjective opinion, 4e and to a lesser extent 5e both made unwarranted changes to lore so that the setting would explicitly revolve around adventurers. If you like that, more power to you, but it's just a preference.
Do you make a habit--or, indeed, even a one-off fling--of playing
anything else?
Because I would be genuinely shocked to hear that even 1% of players play D&D in a way that doesn't involve going on adventures, and thus, involves
playing adventurers, who are people that go on adventures.
It's like saying that there should be extensive rules and descriptions for devaluation of goods due to market concerns and carefully-designed rules for epidemic/pandemic spread. These things are just...not useful to the vast majority of players, and I'm counting DMs in that. If all you care about is that there's a place that "thing made of fire" comes from, there are
far better alternatives.
Spending a dozen pages talking about a place no one can go to, with events that are never relevant, orchestrated by factions that never intersect with the accessible world, solely so you can have an explanation for why a handful of creatures sometimes, occasionally, appear? It's just wasteful. There are much better things to do with those twelve pages.
What would you have in place of the Elemental Planes? There is 4e's Elemental Chaos. There's World of Warcraft's Elemental Plane, which resembles a tectonically active Material Plane world beset by all sorts of natural disasters. I wouldn't matter the latter in D&D.
I'm fine with the Elemental Chaos. Anything taken from WoW should be scrutinized to the nth degree because it's the same "calling it rotten garbage is an insult to rotten garbage" issue. You could do something like Zeitgeist, where planes exist but are largely inaccessible other than calling stuff from them. Or something like Shadowrun, where it's a bit silly to suggest that there needs to be a "plane of fire" in order to have spirits regarding fire appear. In my home game, Al-Akirah is the "elemental otherworld," a place suffused with elemental magic, to the point that regular animals and plants are innately aligned with elemental powers there, and elemental spirits spontaneously manifest out of the ambient energy present...but it's all mixed together unless separated
by things like those animals, plants, and spirits, or the sapient denizens (which, for the area corresponding to the region where the players live, are genies and their attendants/servants/slaves/wider populations.)
There are many options. We can do much better than "plane that is fully, 100% literally
nothing but empty air, except for the spots we've added that corrupt it with non-air stuff so that there's actually something to do." We can have politics that flow back and forth, places of commerce and diplomacy, wild and alien entities, without needing to harp so hard on the "and there's an infinite, empty ocean of pure water where nothing ever happens and no one interesting can live, let alone does."
One person's garbage is another person's Kimchi or thousand year old egg. As someone who started gaming without All the garbage to dig through i'll say this. Be careful what you wish for......All that garbage is far better than relying only on your gaming company to provide what you want.
I'm a 4e fan. I'm
long past "relying" on WotC for a damn thing.