If Jackass started now, it would be a completely different beast. It would still be silly men, performing silly and dangerous stunts, but wouldn't take the form of a television show. Jackass would be a series of online videos, MTV doesn't really air shows like Jackass anymore, times have changed.
We appear to have come full circle, 'Jackass 3.5' is being released episodically on video site Joost. 'Episodes' so far have mostly taken the form of one stunt per episode, and this format works perfectly for Jackass, it's as if when they started out they were ahead of their time.