Desdichado
Hero
I know that there's not a lot of agreement on what exactly is and isn't OSR but I think that most people would agree that fidelity to the older rulesets, i.e. retroclones is kind of a minimum baseline. See this (admittedly long) four part blog post for instance: A Historical Look at the OSR — Part II think it gets muddy because the OSR is sometimes treated to include retroclones (which clearly land in the duplication category) and other more divergent rules sets. Probably your point would be more clearcut if that wasn't the case.
It's just that rulesets and playstyle are not necessarily tightly bound. My preferred rules aren't terribly different from OSR with some houserules from other games or editions, a kind of OSR adjacent ruleset if you will, but I don't really embrace all that much of the OSR playstyle. It's more like playing a fantasy X-files or Call of Cthulhu with a ruleset that's kind of like Shadowdark or Knave 2e that ignores anything related to dungeons, gp=xp, etc.
That's why I say I'm sympathetic to the OSR in a lot of ways, but I don't consider myself part of that movement at all. But just from a raw rules perspective, I'm closer to them than anything else. From a playstyle perspective, I rejected that playstyle way back in the 80s and have never second guessed that decision. It's hard to say you're OSR I believe unless you accept, even if not perfectly, both the retroclone rules and the OSR playstyle.
But yeah, you're right. The OSR as a term is tossed around pretty casually, and is sometimes little more than a marketing gimmick for any indie games that looks vaguely "oldish." Makes it difficult to discuss and be on the same page.