Which was all based off the 3rd edition SRD. You can read about the creation of OSRIC - that's literally how it happened. They had to "reverse engineer" the older games based on what was allowed in the 3rd edition SRD.
Yes, I know that. That is exactly what I was talking about.
But you don't seem to understand what that actually means. The OGL (and SRD) allowed the foundational elements of D&D (classes, stats, terms) to be used- in other words, to "reverse engineer" the old rules (with some improvements) using the scaffolding,
not the rules.
Which meant that on the one hand, you had nascent publishers (Necromancer Games, Troll Lord Games, etc.) that released "old school feel" 3PP for 3e. But that's not OSR.
OSR products were born of the forums (Dragonsfoot, K&K, ODD74) and the people on them, which led to the creation of games that were TSR-compatible, but not 3e compatible. Such as the first game- BFRPG.
OSRIC was second. But OSRIC, importantly, was 1e.
Not 3e or 3e-compatible. While it had some changes (such as the loss of the never-lamented weapon v. ac table), it was, for all practical purposes, AD&D.
And that's what you're missing. Saying OSR is 3e is misleading at best, because it's not. It was very much a reaction against 3e, for people who felt 3e was anathema.
But sure, maybe I should read about it???