i think you are hitting on the right lines with fashion. you just have to look where the "young" riders are now, on their biketrials bikes.
i am 21 and at uni and have competed at higher level of trials (ish) and found that it is not the older bike pushing me out but the difficulty of getting to the events/practice and storing the bike whilst at uni. so now i have gone on to bike trials and am finding it a very easy sport to do logistics wise, the bike will go in the back of my car and i can keep it in my room at uni. if i want to ride i go to the end of the road or find a spot in town. there is also a huge trend on creating videos of a very high standard from an editing stand point, plus the modification market is massive to individualizes your bike. i know i am stating what most people already know, i am just trying to link it in.
so i disagree with the money aspect as i know of loads of guys with