..With the proviso that every now and again someone sneaks in something radically different, like Whitehack’s very open ended (almost FATE-like) spells, its dice bidding (!), or Beyond the Wall’s super-collaborative map-making process, which feels a lot like Dungeon World.

I honestly think there’s a sort of OSR-ness score you could compute on the basis of look, appeal to nostalgia, mechanical similarity, playstyle similarity, ‘subcultural affiliation’, layout styling, and other things.  Some of these OSR games are basically reprints of B/X, while others are quite different mechanically, but happened to grow up in OSR-friendly communities with liberally applied ‘eau de OSR’.