In his interview in The Paris Review, S.J. Perelman was asked about the decline of literary humor and his reply seems as true today as it was when he said it, back in 1963. Here's the exchange:
Interviewer: Mrs. [Dorothy] Parker has said that there aren't any humorists any more ... except for Perelman. She went on to say, "There's no need for them. Perelman must be very lonely." Are there humorists? Is there a need for them, and are you lonely?
Perelman: Well, it must be thoroughly apparent how many more people wrote humor for the printed page in the twenties. The form seems to be passing, and there aren't many practitioners left. The only magazine nowadays that carries any humor worthy of the name, in my estimation, is The New Yorker. Thirty years ago, on the other hand, there were Judge, Life, Vanity Fair, College Humor, and one or two others. I think the explanation for the paucity of written humor is simply that very few fledgling writers deign to bother with it. If someone has a flair for comedy, he usually goes into television or what remains of motion pictures. There's far more loot in those fields, and while it's ignominious to be an anonymous gagman, perhaps, eleven hundred dollars a week can be very emollient to the ego. The life of the free-lance writer of humor is highly speculative and not to be recommended as a vocation. In the technical sense, the comic writer is a cat on a hot tin roof. His invitation to perform is liable to wear out at any moment; he must quickly and constantly amuse in a short span, and the first smothered yawn is a signal to get lost. The fiction writer, in contrast, has much more latitude. He's allowed to side-slip into exposition, to wander off into interminable byways and browse around endlessly in his characters' heads. The development of a comic idea has to be swift and economical; consequently, the pieces are shorter than conventional fiction and fetch a much smaller stipend.