Cloth can be sold for more the cotton.
Beyond actual buildings, woven cloth is one of the earliest signs of growing civilization. The creation of textiles requires tools, training and knowledge so that craftsmen may process raw cotton, wool or flax into usable, wearable cloth. Such techniques developed independently across the globe.
Cloth became a major industry in Europe in the 18th century. The explosion of cotton growth in the New World meant that textile mills in the Old World could become extremely profitable enterprises. Within a hundred years, the continual technological advances of the textile industry would be one of the major contributors to the onset of the Industrial Revolution.