i think it's the reflections that lacks the depth. try snapping some pictures against some contrasting light source.

can try Parkson, I think i saw some products there.
but anyway, I don't see why should we spend the money on shampoo instead of the "after wash" products. for me, i am using Kit shampoo to wash but always use auto detailer and a few micro fibre cloth to remove excessive dirt and make it shinier