note on ''Should we use more synthetic fabric as it would free a lot of agriculture land for food crops?''
Synthetic fibers do not need any agricultural land to grow. Thus from that point of view use of synthetic fibers can save agricultural land for growing food crops but synthetic fibers are nothing but polymers which are chemicals. They are non biodegradable. They have a hazardous effect on environment if used in excess. So one should use synthetic fibers in such a manner that their good qualities are enjoyed by minimizing their hazardous effects.