VengerSatanis
High Priest of Kort'thalis Publishing
(O)D&D and Basic (of which there are several kinds, actually) really shouldn't be conflated. I agree with trancejeremy that "OSR = TSR era D&D/AD&D" but would extend that to other TSR RPGs like Empire of the Petal Throne, Metamorphosis Alpha, Gamma World, and even Boot Hill, Gangbusters, and Top Secret, and maybe even Marvel Superheroes. I might even be inclined to include some of the non-TSR RPGs like Tunnels & Trolls, Villains and Vigilantes, Traveller, Chivalry & Sorcery, and RuneQuest, and perhaps even Bunnies & Burrows. (Yeah, I went there.) There are others but those are good examples. As such, the OSR isn't simply about compatibility with early D&D nor even about products published to emulate early D&D, but about a whole movement to play and enjoy early RPGs, and in some smaller sense includes some newer games and supplements that emulate early RPGs of many stripes.
What you said there is similar to the end of point #3.
As for the rest... OK, thanks for the comment.
VS