I'll throw in my 2 cents. I am currently 27 and am still in university so I can give some insight as to the mindset of most college aged kids.
You have to consider the fact of immaturity. No matter how much you preach no matter how much you provide examples, the immaturity (and testosterone) of most people under 25 cannot be overcome with logic. For most people in that age group, your sense of logic doesn't become really prevalent until you get older and wiser. Not just when it comes to motorcycling but life in general. How many people actually listened to their parents when they were teens let alone when they hit their twenties regarding bad friends, bad girlfriends, wasting money, partying too much, and not taking life (and school) seriously.
I know I am definitely guilty of this myself, not only when it came to not listening to those who have gone through life, but also the specifics as well such as ATGATT.
There are many things with life in general I regret doing that could have been avoided if I had just listened to the people who were there to give me advise. But I needed to experience those pitfalls to make me realize the error of my ways.
When you are young you think you are invincible PERIOD. You think "that old person can't relate to me, and their advise isn't worth listening to." Same concept goes for motorcycles, the logic to wear gear doesn't hit home for many people in that age group until they get into an accident. Let alone the logic that a 600SS or 1000SS bike is ridiculously fast and scary for a inexperienced rider. Its like giving a 21 year old a Trans Am. I know, I had one, and am lucky to still be around considering all of the dangerous situations I put myself into.
Another part of it is also comfort and aesthetics. I know I look weird and get looks coming out of my office in the morning (i work overnight) wearing my motorcycle pants that swoosh when I walk
with the rest of my all black gear especially as people are coming in with business attire.
I myself am guilty of deciding to only wear jeans instead of the motorcycle pants on occasion. But I noticed myself missing my motorcycle pants after I had to send them in for a warranty claim. Now I don't want to ride without them. That sense of logic didn't kick in until I experienced riding without them after experiencing riding with them. In all honesty I don't think that logic would have developed in my mind if I was younger. The pure aesthetics of the situation would have averted me from ever buying motorcycle pants.
Unfortunately that is the reality of the fact. I know for the older and wiser members on this board, that is a hard thing to understand. But I feel it is the truth. Many teens and people in their twenties will not take wearing gear seriously until something happens to them due to that mindset that that it can't happen to them. For some even that will not help them develop the sense of logic needed to understand the concept and importance of ATGATT.