Not really, mostly its supply and demand, the 5k diamond is 5k because of its rarity, same goes for rare art etc...
If you are a billionaire you don't want a fake rembrandt painting sitting on a wall, or your wife to be wearing fake or grown emeralds just because you save a little cash. You don't care if most people or even everyone without a magnifying glass couldn't tell, you would know.
In terms of the massage girl, if she's giving the best massage ever then she should be working somewhere making decent money and I still think that the bathing in flowers, relaxing music and look and feel of a spa is worth much more to me than a dingy little place with a dividing curtain.