Two things. First, traditional handmade wool carpets are a function of altitude. Second, the value of most carpets is related to the level of feminine involvement in the weaving process. The first statement may seem self evident as higher, colder altitudes demand the warmth and insulation of wool. A point is reached with rising latitudes where the summer thaw is too short for the warm-fingered time-intensive work required. There is more than meets the eye however with the second statement.
Take a look at the "carpet belt" which stretches across the world from Morocco in the west to China in the east. For instance Morocco has a traditional carpet weaving culture synonymous with the Berber and Arab tribes grazing their flocks in the mountains and high plains. Boys tend the sheep, men prepare the looms, and the women weave. Coastal weaving is of the flat-woven cotton tapestry type carried out in ateliers with flying shuttle looms manned by skilled men. An exception is modern commercial weaving where rugs are hand knotted with an eye on western markets. These are made in similar ateliers regardless of country or tradition. This scenario holds true across the "carpet belt".
The modern countries of Turkey, Iran, and Afghanistan, the core of the "carpet belt", are almost completely plateaux and mountains. The surrounding countries of Syria, Iraq, Kuwait, the Gulf states, India/Pakistan are mostly under 1000 metres and traditionally produce only flatweaves. The cold northern neighbours, Russia and the "Stans" are mostly at lower altitudes and preferred to make less labour intensive felt rugs. India/Pakistan has a royal carpet weaving culture as opposed to an indigenous grass roots one that stemmed from 700 years of ruling mountain Afghan dynasties.
Distinctive also are materials. Cotton requires broad-acre farming which presupposes flat lowland conditions and is so intensive in it's land use it requires land ownership. Cotton fabric is less insulating and cotton weaving is logically a lowland occupation. By contrast sheep pastures are usually elevated and are mostly lands held in common. Wool production and wool weaving are elevated occupations. This appears to be the case generally but many types of traditional mountain village rugs are part cotton in that they have a cotton warp (the longitudinal base threads). The important connection here is commerce.
Pure wool rug making is basically value-adding to a family's flock of sheep. All materials come from the family or are produced by someone in the wider clan. Cotton is a trade commodity that must be bought or traded by the mountain rug making people to use instead of their own wool. This implies a cash component in the making of a rug, adding a subsequent cash or trade value to the finished product. Cotton therefore is often found to equate with commercialisation of the rug making process.
Look at loom technology and find the number of shafts or "sheds" inversely proportional to the geographic elevation of the loom. Traditionally, knotted pile rugs were made at altitude by family units using simple one shaft looms, while lowlanders produced flatweaves and mass produced rugs. The lowlands are the domain of the fine silk brocades, shawls and other fine clothing fabrics.
It is interesting to note that religious fundamentalism seems to be a function of altitude, or lack of it, calling the lowlands and deserts home while the mountains and the high plains are home to a more conservative adherence to traditions with a more liberal outlook. Look at a map of say, the USA and find that topographically, the "Barble Belt" equates with the "green" areas. Do this with maps of relevant parts of Asia for a similar result.
There are connections between the low country, mass production and religious fundamentalism, and the high country, family weaving and liberalism. Mass production involves working men with jobs outside the family whereas family weaving is done by the women of the house.
Social mores also seem to follow this altitude-specific way of life. Travelling from the shores of the Mediterranean Sea to the Mountains of Kurdistan or Karabagh one sees more women and fewer veils. Similarly from the Persian Gulf to the mountains of Iran and Afghanistan one sees increasing liberalism, even Sufism, and personal eccentricity and creativeness coming to the fore.
Traditional knotted pile weaving flourished in the freedom of liberal but conservative communities driven by family, community and a complex and nourishing mysticism. Family designs, clan motifs, and talismans are all part of a rich vocabulary that evolved over long periods. Like musical harmonies these designs form colourfields in an endless interplay where rug weaving becomes a form of prayer, of connection with the universal, a humble submission to the will of God, the definition of Islam. It is this that gives the Oriental Carpet true value.