Auto-Tune had reached its peak a long time ago. The majority of people who used it as a prop to cover-up their singing issues (in other words they couldn't sing!) In mainstream music Peter Frampton used it as back then it was called the "Golden Throat". Even though he had major success with it, many indie groups at time were using. The next "big" star to use Auto Tune was Cher. Like Jay-Z and many others, Auto-Tune was flooding the industry with a lot of whack music. Then acts like T-Pain couldn't perform live because he couldn't reproduce what he did in the studio live. Now that should really tell you something about him and others who used Auto-Tune. Have you noticed in the last couple of months we've heard nothing from them.
There's nothing wrong with innovation and auto tune presented another option to Hip Hop. There is absolutely nothing wrong with that, but everyone jumping on that wagon caused the issue because all these rap dudes dont need to be on Auto-Tune. Just cause your career didnt pop using your regular voice doesnt mean there's more hope with the vocoder.