Now if 5E had done what some of the early design discussions suggested and had create a sort of bare bones d20 system with setting and play style creating additions - I think that would have been amazing. One could have had a warbands/tactical skirmish system set in Spelljammer land with space crews battling each other, a heroic wilderness game on Arathas, a Greyhawk high lethality dungeon crawl to demesne game system and a Forgotten Realms fantasy heroes light tactics game... rather then simply the last promising to deliver all the others if one just imagined hard enough.
To be fair, there are a lot of systems that do exactly that, except without the D&D branded stuff, of course. GURPS. BRP. Savage Worlds. FATE. None of them are anywhere near as popular as D&D, but yeah; I mean, it exists. Arguably, D&D did that too (how well is subject to debate) during the third edition era when it had two SRDs, the "regular" one and the Modern one, and all kinds of add-ons were meant to make "D&D" do all kinds of things. This was especially true when the 3.5
Unearthed Arcana book was released, which explicitly was around changing mechanics and playstyle into various models.
I think it comes down to the fact the OSR itself narrowed down what they mean by OS to basically 1977 - 1983 B/X and 1e with Gygaxian dungeons and sandbox play. The vast majority of material keeps to that area and there is little beyond that. There is exactly one 2e retroclone and it's widely panned. No one is producing settings like Ravenloft or Forgotten Realms, just Greyhawk clones. Story-based narrative play is shunned, and Hickman's revolution is seen rather negatively.
Depends on what you call the OSR. The "original" OSR died years ago when all of the games had retro-clones available for them. The next wave of the OSR, which just adds more modules, more options, and stuff like that died years ago (although years later) probably around the time Google+ died. The current "OSR" has changed the term into being more of a playstyle than a ruleset, or even a family of loosely related rulesets. All kinds of games that have little or no compatibility with pre-3e D&D but which still claim to be "OSR" because they champion the OSR playstyle to a greater or lesser degree are the darlings of the movement these days.
That said, you don't need to hang out on r/osr and argue about the merits or OSR bona fides of Black Hack, Mork Borg, or Into the Odd to make use of all of the work that's been done in the nearly twenty years or so since OSRIC was released. What exactly are you wanting from the OSR? New settings like in 2e? They're out there. I agree; that's not really the focus of the OSR, but there are some. You want something like trad-style adventure paths or mega-adventures that aren't just hex-crawls or megadungeons? There are some, even though, as you say, that's not as much the focus. But they're there. That's the beauty of a movement that's fairly diverse and has been around for a long time. There's all kinds of things available in it. Regardless of what the trends of discussion might be, there's someone else doing something else in it too.
