I'm 20 and dress pretty preppy so my go to brands happen to be Polo, JCrew, Brooks brothers, and Tommy Hilfiger. Although the trend in now is layering, ripped/biker style jeans, etc it seems as if brands like topman, zara, and H&M are taking over but will soon stop once something else comes up. Plus the quality of the clothes from those companies is horrible (I guess you get what you pay for) even compared to Polo's recent quality. You'll always need a nice suit/collared shirt/polo no matter what and thats what Polo is good at. They're down now because dressing essentially preppy or "collegiate" isn't in right now with the younger crowd. However I've never found Polo to necessarily be a brand chasing the attention of the young folk (with the exception of Rugby).
Although I used to wear fitteds in highscool, the only time you'll catch me wearing one now is if I'm playing in a baseball game. Snapbacks IMO are just plain unacceptable