OK so it's been busy lately but I do intend to get back to this and post some more thoughts, including the "so what are you actually thinking about doing" part. Also make the site a bit less ... uh ... spartan.
In the meantime: There's this new Overture Maps Foundation thing which sounds great on the surface - and right in line with the sorts of things that I'm thinking about here - but led by, among others: Microsoft, Meta, Amazon? Meant to be "complementary" to OpenStreetMap but I'll admit I'm a bit skeptical.