Madeline KAHN, other best ditzy comediennes like ZaSu PITTS?

KAHN's "Mixed Nuts" was just on and she just was so perfectly hilarious as in her Mel BROOKS movies. My mother taught us hilarity from ZaSu PITTS (Wiki says it's pronounced say-zoo). Wiki also says KAHN was fired a couple of times, once by Lucile BALL in "Mame," hmmm. Well, she was also eager to go so that she could get into Blazing Saddles.

It seems like the ditzy comedienne character is so specialized that few can do it, and it takes special writers/directors to support it? With Carol BURNET it's more like she's not so immersed in the character, that's she's sort of breaking the wall and asking us whether we are getting what she's doing?