Well it depends on on the persons taste. Some persons like wears that of high quality and for that reason, go for the best undermining the cost. Others feel its just an underpant and it shouldn't be a thing of much priority thereby going for lower cost. Its all about the mind set. It's not bad if you have the money to buy it
Most times people don't understand that those things that are not seen and what people take "as not important" are what one really needs to take note of.
As for the pants or briefs, 1k isnt too much for something that you would likely wear for over 3 months. Come to think of it, people who say its too expensive end up spending that 1k on food that one would definitely pass onto the toilet.
Yes based on budgets it could be termed luxury, but when things improve the taste of one should also improve.