I don't know how you could possibly know all the bands in a city of millions, unless those bands are already well known. I grew up in a city of millions in the US. I'd estimate more than 100 new bands were formed every year. Most of them never got gigs, but that's because they never got a chance. Admittedly not all of them cared, but most did.

I think we're just gonna disagree on this one, as I'm arguing from a theoretical perspective (you can't possibly know how many bands there were) and you are arguing from a pragmatic perspective (anybody in the scene knew everybody).