Although slightly off topic from the blue jeans, I think this at least lends credence to the argument. When you think about human tech and what we have done and how we have done it, not a lot has changed in concept. When we started fighting one another with weapons we threw rocks, well that just evolved into sharpening the rock and throwing it, then sharpening the rock and putting it on a stick and throwing it, then sharpening the rock and putting it on a smaller stick and shooting it from a bow, then making it metal, then making the metal smaller and shooting it with gun-powder. A bullet for all of its advances and accuracy is no different in concept than throwing a rock, we just found better ways to do it; so why not 500 years in the future would we still work with that concept? And human armor hasn't changed either in over 3000 years, why should it change in the next 500? We layered animal leather over our bodies to protect us, then breastplates, and now we do the exact same thing but with better materials; we use ceramic plates rather than deer skin, but we are in no way using a new concept. I think the blue jeans will be around, the overalls, and every other durable standard piece of equipment that we have right now. After all, robots harvesting cotton will still be pretty cheap, and those colonists on harvest didn't need space suits, they just needed something to cover their business while working on those robots out in the fields.
My two+ cents anyways