I think perhaps you are being a bit generationist! Although serious music fans do actively follow music trends, a lot of people keep listening to the music that was popular when they were in their late teens. Not only that, I think that they tend to keep wearing the clothing that was popular then too. I certainly still listen to 70s and 80s music. Although some of the 90's stuff is OK, anything since sounds really bland to me. And there's a fair chance you will still be listening to the same music you listen to now, in 20 years time too.
There's a thought that comes out of those beliefs that really disturbs me, but thankfully I won't be around to see if it comes to fruition...
That is that the men that were born in the 80s that wear their pants slung really low, showing off their underwear, will still be doing the same when they are in their 80's and 90's... truly disturbing...