To answer the initial proposition of the thread:
1) harkening back to older styles of music has an inherent emotional detatchedness that comes with it. It’s pastiche, there’s a degree of distance.
2) as such it follows that genuine- or at least potent- emotional expression has to be done through modern forms and styles of music as they don’t carry the baggy age of being pastiche.
3) increasingly since James brown, but really ramping up with rap and rave music- modern music has been centred around rhythnic ideas.
4) rhythm often is processed far more in terms of movement or information than it is emotional. Even when it does conjur feelings, they’re not ones we’d consider ‘soulful’. Funkiness is about ego. Jittiriness is about anxiety.
5) as such we are unable to use either modern nor old styles to create new soulful music.