Okay, so I've been pondering on this for a bit and I wanted to see what you guys think.
Auto-tune has become pretty prevalent in modern American Pop, R&B, and Hip-Hop music (I'm not sure about the international scene). We have a lot of artists who probably wouldn't be around without auto-tune, and we have a lot of artists who would be the last people to ever need it using it (Mariah Carey comes to mind). Auto-tune is that "new sound" right now. It's what's hot and hip. So it's showing up a lot!
It reminds me a lot of the synthesizer back in the 80's. It was huge! It was everywhere! It was that "new sound!" Eventually, however, it got old and, though it is still widely used, it's use is more subtle. It's not quite center stage anymore like it was back then, nor is it as prevalent.
I think auto-tune is going to go the way of the synthesizer as well... it's just a matter of time. That makes me wonder about the artists who rely heavily on it, like Lady GaGa and Ke$ha. I can see Lady GaGa surviving without it just fine. She has a lot of talent and has built a reputation for herself that will allow her to re-invent her music and still keep her fan base (like Madonna). However, Ke$ha, though (and you may disagree) I do believe she also has a lot of talent, she's a bit more of a one-trick pony. I don't think she will survive the auto-tune fall-out. Though, you never know. She might just pull it around in time.
Anyway, that's just my thoughts on it. I don't really know what spurred this thought process but I figured I'd share it anyway.