I had a thought about the nuum the other day as well, might as well share it now, whatever.
I was thinking it's dead cos the waves of migration that kicked it off have calmed down and there isn't that sense of difference you needed anymore. Like it all popped at a certain point cos the music of afrocaribbean origin had reached a level of maturity which allowed for crossover.
But that's now happened, and there isn't really any kind of correlate for now, in terms of big migration. So it's all just recycling and going over.
I mean the wider point is that we are living in a declining country (I mean the UK).
There have been actually, huge waves of migration, but the nuum was really about the West Indies. There was a relationship there with Jamacian music. Since then you've had, to name a few
Somalian, Polish, Turkish, Vietnamese, Romanian, Lithuanian, Portugese, Columbian, Algerian, Moroccan, Egyptian, Albanian, and of course Nigerian and Ghanian (not to mention Gambian, Cameroonian, Angolans) It's a vastly more multicultural London than it was in 1993. Far more complex.
how that might pan out in music is not obvious. It's clearly ridiculous to posit some future amalgamation of all ethnic, cultural influences. It never works that way. (Some bagpipes over some daburka, with a nose flute and some reggae bass) you may get what Barty wants, which is localised scenes demarcated by ethnic/cultural/national origin, some of which could cross over to a larger audience. That doesn't seem inconceivable. Polish donk, Turkish reggaeton etc. Afrobeats was/is this to some degree. Asian garage was this is the late '90s.