Standup comedy is hard and Mr. Rickles was in a class of his own with no competitors. There have been many silly standup comedians, think Steve Martin or other site gag comedians like Carrot Top or Gallagher. There have been many observational comics like Richard Pryor or Carlin or Seinfeld. There have been outrageous comedians like Sam Kinison or Andrew Dice Clay. There has never been another Rickles, he worked without an outline or even a joke, he had complete confidence in an industry where everyone dies on stage eventually.
In an industry where comedians are known for stealing from one another, nobody could ever accuse Rickles of stealing from anyone and he couldn't be stolen from. His genius was in his delivery and speed. You cannot just learn that.
As a person Mr. Rickles was incredibly respected by other comedians. That will be shown in the coming days. With over 60 years in standup he managed to impress other comedians with his warmth and humor in person.
My prayers and wishes go out to his family and friends.