Ok, so none of them can sing, and they all have publicists who create their personalities, and all their songs are ghostwritten - but to see how Autotune has changed music:
Here's Wannabe Gangsta "Ke$ha" with "her" hit Tik Tok:
https://youtube.com/watch?v=iP6XpLQM2Cs&feature=fvw
And here's a 40 year old woman off the street who had never heard or seen the same song after two hours in the studio with Autotune:
https://youtube.com/watch?v=XQbpF0_5-c8