The fact that it was consciously (some would say self-consciously) evoking a specific bygone era of soul music?

Before Kedar came and branded it "neo-soul," critics were throwing out labels like "soul revival," "neo-classical soul" "new classic soul" and "nu soul" (which is the title that stuck in the UK)... all of them strongly suggest the point that it is a very deliberate throwback to the past.