Besides the "testers" that can taste differences have become attuned to that over years of "training". For most people, we won't know a difference even if there is one.
I can tell the difference with Whiskeys and Scotch to a point, but that's the point where things get ridiculous and it makes little to no difference to me.
Yeah, the returns diminish rapidly. Scents and tastes are also linked closely to memory and emotional experience. So if someone can setup a pleasing atmosphere while charging you exorbitant amount of money for a nice meal, you will think the food actually tastes better.