No, you have the wrong idea of "idol". American idols are not actual idols - think Kim Kardashian. While she has some loving followers, the rest of the American public watch her out of disgust and shock. And secondly, American TV =/= American music industry. KK would not be able to put out a single that would do well on the charts.

Simply put, people like you and me like SNSD because they're gorgeous, funny, cute, and talented. BUT, think about it - Americans don't listen to people like Ke$ha and Katy Perry for their wonderful personalities, they listen because the songs are cheap and catchy and good billboard runners. Songs like Hoot, Oh! and Run Devil Run would never be able to compete in a US market. They only did amazing in Korea because they're loved over there. I posted this awhile back in r/kpop, too:

They're marketed in a very specific way, and it'a not something Americans are used to. They build an image through media/variety shows and have a fanbase so thoroughly dedicated it's almost terrifying. SNSD aren't allowed to date, have scandals, publicly act out, etc. The idea for the fans, is that "there's still a chance for me". Americans are content as casual fans, and probably aren't ready for that kind of intense loyalty.

SNSD is INSANELY popular in Korea. Their giant fanbase makes up all of their sales. When's the last time you've seen a similar following for an American group? Justin Bieber is the most comparable thing - but his fans are all 12-16 year olds. SNSD would appeal to men (their age and older) but American men obsessively fanboying over SNSD would be shamed here, no question.

TL;DR Americans who buy music are CASUAL listeners (they listen to the radio and buy music on iTunes). Koreans who buy music are FANS (they watch every performance, record every talk show, download every fancam, buy every wall calendar). SNSD is a perfect market for the latter and Americans won't buy into that kind of thing.