For three decades, Mr. Cavett was the thinking person’s Johnny Carson, embodiment of an East Coast sophisticate. He wore smart turtlenecks and double-breasted blazers, had more cultural references than a Google server and laced martini-dry witticisms into lengthy, probing talks with 20th-century luminaries including Bette Davis, James Baldwin, Mick Jagger and Jean-Luc Godard. A Renaissance salon in a rabbit-ears era, “The Dick Cavett Show” was woke some 50 years before the term came into vogue.