Do you believe that they have been taught that way from just their parents?
Human beings are born selfish. It takes time, chinich, maturity, and working on oneself to overcome this, and truthfully, very few people ever do, and much fewer to the point of not caring about gashmius at all.
So, many bochurim want a good quality hat. Many of these same bochurim will end up living lives with very little gashmius, and great sacrifice for ruchnius, or even better, histapkus to the point that it’s not even a sacrifice.
This (although I believe the final number is small as a percentage, it is still “many). However, it can be done even for a bochur if you are willing to start early. It makes for a much better bochur and eventually, a head start in becoming a Talmid Chochum.