Johnny Knoxville burst onto the showbiz scene in 2000 as the de facto host of MTV’s Jackass, a strange, hysterically funny reality show that became a surprise smash hit and launched Knoxville to stardom. He followed it up with three hit Jackass movies and acting roles in several other films. And then Knoxville…pretty much up and vanished. Why? Here’s a look at the real reasons we don’t hear from Johnny Knoxville anymore…