Reporting in at 19 yrs old. I have always liked "good" sound, but didn't have any money to spend till recently (My parents were very controlling of what I spent money on, no such thing as my "own" money). My first proper headphones were hd595's which I got for 17th birthday. Most of my friends thought it was a waste, but slowly I convinced them otherwise. One of my college friends was the type to buy the cheapest possile headphones. I mean, this is a guy who would buy a 3-pack of coby headphones for $5 because they "crap out" every couple of months. However, he spends a lot of time in my room, and i think I converted him: a couple days after I bought my hd650's (which I got a couple months ago), he came and asked me if I'd sell my 595's, lol.
As mentioned earlier, going from lo-fi to hi-fi is like "whoa, that sounds good, but I don't really care", but if you get someone used to hi-fi (meaning listen to it a lot), they won't liek lo-fi stuff anymore. I think that's what happened to my friend (not the only one, but he is the best example). I have KRK Rokit 6's as my speakers, and spending so much time in my room, he got used the vastly superior quality of that sound over the coby's (Although for the first year that I knew him, he insisted that it was a waste of my money).
Thinking about it, I think budget also has a huge factor, and "older" people tend to have bigger budgets which is why it might *seem* like they prefer higher quality sound. The fact that people notice the difference, and then say it doens't matter, means that if it cost the same, they would get the hi-fi equipment. But it doens't cost the same, and even with entry levl hi-fi (or mid-fi, as some would call it), the $50 needed to enter could be "better" spent elsewhere. You don't need to convince people that hi-fi is good, just that its benefits are better than a new cell-phone or other gadget. Face-it, gadgets have that "cool" factor to them. People think a thin, sleek iphone is cooler than a fat set of headphones which sound epic, but make you look like an "wierd". (I dare someone to go to a party wearing those huge cans).
On the other hand, a bigger budget means you can get both