the 60s / 70s soul thing is maybe the best example of how some genres have only a short period of time where everything (social, musical infrastructure, the kind of people who the world is creating) comes together and allows such things to be created. its not simply that the music made in the same genre sounds like pastiche, sitting in the shadow of the greats. it becomes impossible to make anything as good even ten years later because the people and the technology have changed.
it's not just the bartytune influence. everyone grows up singing differently in different eras coz they're all copying each other. that particular period of the us african-american world (i don't know much or indeed about it) produced a really beautiful and gracious form of singing. there's stuff about now that's broadly similar, like morning[a]BLKstar or however it's written but the window for producing that quality of singer was short.