Durable cotton has longer fibres so that they won’t break off as easily as the short fibred varieties. I guess that is the reason why.
“ Now, what's important to note is that the quality and the price of an item are not always related. Some types of items are easier to manufacture and get right than others, which is why it is totally possible to find certain well-made items at affordable shops. At the same time, just because an item is very pricey, that sadly does not always mean that the manufacturer used all of that extra money to up the quality of the garment.”
Edit - citing the source [0]: https://anuschkarees.com/blog/2014/05/01/how-to-assess-the-q...
Same with the $500 pair.
It’s just difficult to tell if one can’t evaluate quality oneself.
And a second hand store, specifically, because the clothes there being used reinforces the survivorship bias - bad clothes don't make it through recycling.
It's gotten better, but I had some early Patagonia organic cotton jeans that basically began to disintegrate. There are some hemp-cotton blends that are fairly soft.