@Mammmood - I agree that synthetic materials are not as delightful to wear as natural fibers, but they can be cheap, and more importantly efficiently produced for mass consumption.
Not everyone likes wool. Polyester always has its detractors but there are people who will wear it and not think twice.
What I like about the melt spinning process is that it seems to be quite straightforward and easy. Melt a whole bunch of polymer, strain it through the holes and cool it quickly. I don’t know how easy it is to thread wool and stuff like that, but from what little I’ve seen it seems to be a little more intricate.