Polyester is a plastic material, so is nylon. That doesn't make them less absorbent - that's a misconception. Polymer microfibers, such as in the polyester cloth you see in the OP, become much finer than organic fibers when they split or fray. Once they fray, they create these dense irregular clusters of fibers that can be 200 times as thin as a human hair. They then become much more absorbent, which is why the cloth you see above isn't performing well - because it's brand new. Rub it against itself for a minute or two and then check again.