Subject: Great celebrities who have noticeably become obscure

Even though we frequently lament over the passing of a celebrity, we often see people lament and remininsce over their great work. That said, many former great stars become somewhat forgotten for various reasons. Some may be due to cultural changes (too politically incorrect for the present), disinterest in a genre/type of work (Westerns/Vaudeville), or the fact that their supporters were generational and that generation's followers dies out along with the celebrity. Does promoting the youth come at the expense of making possible superior work  of such legends disposable?