The fine essayist Philip Lopate writes about the essay as a genre  and is relatively pleased about how it’s doing:
I am an essayist, for better or worse. I don’t suppose many young people dream of becoming essayists. Even as nerdy and bookish a child as I was fantasized about entering the lists of fiction and poetry, those more glamorous, noble genres on which Nobels, Pulitzers and National Book Awards are annually bestowed. So if Freud was right in saying that we can be truly happy only when our childhood ambitions are fulfilled, then I must be content to be merely content.
I like the freedom that comes with lowered expectations. In the area of literary nonfiction, memoirs attract much more attention than essay collections, which are published in a modest, quasi-invisible manner, in keeping with anticipated lower sales. But despite periodic warnings of the essay’s demise, the stuff does continue to be published; if anything, the essay has experienced a slight resurgence of late. I wonder if that may be because it is attuned to the current mood, speaks to the present moment. At bottom, we are deeply unsure and divided, and the essay feasts on doubt.
Well, maybe. (That’s my essayistic side talking.) But over at the New Republic, Adam Kirsch has written a really thoughtful reflection  on a certain kind of writing that looks like the essay — but really isn’t.
The self, then, has always been at the heart of the literary essay. But the new essay is exclusively about the self, with the world serving only as a foil and an accessory, as a mere staging ground for the projection of the self. Formally, one might describe the work of Sedaris, Crosley, Rothbart, and company as autobiographical comic narrative: short, chatty, funny stories about things that happened to me—weird things, or ordinary things that are made weird in the telling. What we now call an essayist used to be called a humorist. Sedaris’s books are sold as essays, but he is plainly trying to be Thurber, not Addison….
Essayists such as Rothbart and Crosley and Sedaris, one might say, represent the prose equivalent of reality TV. They, too, claim to be recording their lives, while in fact they are putting on a performance; and they, too, count on the reader to know the rules of the game, the by now familiar game of meta. What makes this kind of performance different from the performance of a fiction writer is that, by “acting” under their own names, they inevitably involve motives of amour-propre. The essayist is concerned, as a fiction writer is not, with what the reader will think of him or her. That is why the new comic essayists are never truly confessional, and never intentionally reveal anything that might jeopardize the reader’s esteem. “Love me” is their all-but-explicit plea.
I think Kirsch is right. But I also think that these writers end up focusing on the self because, in an age in which there are so many interesting books on every imaginable topic, there’s less apparent room for the essayistic way of doing things. William Hazlitt wrote a lovely essay “On a Sun-Dial” , but today would probably find himself, instead of writing, looking online for books on the history of time-keeping. The kinds of topics that once might have been low-hanging fruit for the generalist of belles lettres are more likely today to be written up by a person of specialist knowledge who wants to reach a broad audience. As a result, this is a great age for thoughtful, entertaining, informative nonfiction; but not so much for the essay as such.