Top artists--musicians in particular---usually have a progression of their careers that involves a breakthrough, a plateau, and then a waxing and waning---or some other development which some may argue is better than their "peak" (i.e. peak of popularity or fame).
Regardless, I have a fascination with celebrity in regard to the sometimes manic proportions to which some acts have driven large audiences. Two that come immediately to mind are Elvis Presley and the Beatles. Between Elvis "the Pelvis" and "Beatlemania," we get a good glimpse of celebrity of epic proportions. To wit:
If you pay particular attention to the audience feedback...it's stupendous the amount of celebrity power these young men had at the height of their power. They had stolen the hearts of girls around the world, bringing many of them literally to tears. They were supported by an international media frenzy. They also attracted the attention of broadcasting/moral authorities with regard to their acts/content, which led to disdain and bans on certain songs. Their influence was far-reaching; their celebrity unprecedented.
However, both acts had later careers that developed into something else entirely.
Elvis progressed into film and an eventual comeback before his death, while the Beatles retreated in large part to the studio and psychedelia shortly before their breakup.
Regardless, it would seem at the late stage of their careers that the craze surrounding Elvis at the time of his breakthrough and the mania driving Beatlemania was in large part a thing of the past.
Do you have other examples of artists at the height of their power? What is the extent of their effect?