I'm not sure I would thank George Carlin and Richard Pryor for what they brought to comedy. Up to that point, comedy didn't need to have profanity. Now if someone like Bill Cosby or Lily Tomlin tried to break into the scene they would go no where, because the "powers that be" won't take them seriously.
A lot of people miss the subtle difference between a real belly laugh, and a laugh this is the result of something shocking or embarrassing. Today's comedians will take a laugh any way they can get it, even if it embarrases the audience, trashes the President/Goverment, or shocks society. Carlin and Pryor get a lot of credit for taking us down that road, as well as Rodney Dangerfield and a few others.