I think this episode of the simpsons is making fun of how people are more preoccupied with cool things rather then cool people. It is basically saying it's not the person that we're really looking at, but instead what they do, and if what they do is considered to be cool then they themselves are cool as well. The episode shows how Homer is considered to be uncool based on his age alone. I thought it was kind of funny to see how listening to classic rock in the 90s was uncool as opposed to now where if you buy a led zeppelin t-shirt from kohls everybody thinks your a bad ass (classic rock shirts from the same place my nana shops is the coolest! ) Anyway, getting back to the point, the episode is more focused on cool things and exaggerates the fact that we are so centered around them.