The success of American Idol has been described as "unparalleled in broadcasting history". The series was also said by a rival TV executive to be "the most impactful show in the history of television". It has become a recognized springboard for launching the career of many artists as bona fide stars. According to Billboard magazine, in its first ten years, "Idol has spawned 345 Billboard chart-toppers and a platoon of pop idols, including Kelly Clarkson, Carrie Underwood, Chris Daughtry, Fantasia, Ruben Studdard, Jennifer Hudson, Clay Aiken, Adam Lambert and Jordin Sparks while remaining a TV ratings juggernaut."
Who called American Idol "the most impactful show in the history of television"? (If the question is unanswerable, say "unanswerable")
a rival TV executive