I don't know why, but these are softer and thicker than what is supposed to be the same product from a big-box retailer.  They're a little pricier, but for the extra thickness and softness, they're worth it.  These are holding up much better than the same brand purchased from a local retailer.  I guess Hanes has differing levels of quality based on who they're selling to.  I'll look to Amazon for my next purchase of these.