The human being has primary needs, as eating, drinking, dressing, having a shelter to live in, that have to be satisfied.
When the primary needs have satisfied without problem, secondary needs, as to be elegant, to be trendy, to possess a beautiful house or a huge and very fast car, are generated.
These secondary needs have to be so desirable to seem almost indispensable.
So the human being replaces its secondary needs with the primary ones.
The really rare or unique objects in the luxury world, are very few.
It may be a very precious gem, a rare diamond, an original art masterpiece, made directly by a real artist, with his own two hands, impregnated of his sweat, his tears, his DNA.
These objects are really unique.
All the others objects that are defined luxurious are mostly normal objects without any particular characteristics of unicity, but wisely transformed, with the communicative tools of semiomarketing, into a status symbol.
The real luxury is something precious but immaterial, as the time to spend as we like, that passes away and when has gone, it never comes back; the individual reputation, that is so long to build and so easy to lose; the love and the freedom, that are a gift of the life, without price, but so rare and impossible to buying, and so forth.
These immaterial goods, that are so rare and precious ( and paradoxally, free) are desired by most of mankind, but only few human beings can taste them.
So, the way to create the luxury world is to transform normal objects into luxurious objects, just joining the immaterial concepts as unicity, culture, love, freedom, transgression, sensuality, elegance, etc. (that are meanings, ideas) to bags, shoes, clothes, glasses and so on (that are signifiers, material items, the perceived part by our five senses of the idea).
The ability of a good luxury designer is to transform objects into symbols, material items into signs and to intercept with them the target’s needs and desires.
Then, to limit the number of "competitors" and to allow only to few privileged individuals to feel special and unique, the luxury good must be very expensive.