One day last week, after I spent the best part of an hour opening two days’ worth of post at my office – I work as literary editor of the Spectator – I posted a peevish tweet: “Can we all stop publishing, for good and all, nonfiction books about the future, books about how to change your life, books about what it means to be/how we came to be human, and books about fucking Nazis? For a start.”

This was bad manners, for which I apologise. But it’s a semi-public expression of the sort of momentary eye-roll that’s the occupational hazard of my work. Just as, I daresay, football commentators or fashion writers must now and again wonder what the point of it all is (a memorable French and Saunders sketch portrays someone erupting in a glossy magazine conference – “I can’t take it any more! It’s all so fucking trivial!” – and having to be bundled into a cupboard), so too can literary editors, after a long session ripping into Jiffy bags and finding the same book in three-quarters of them, lose their poise.

But my complaint seemed to strike some sort of chord with a few people. The author of a book about how we came to be human, which had been reviewed in the latest issue of the Spectator, wondered if I was referencing him; I got anxious direct messages from friends working on books about Nazis; and others pitched in with further suggestions of books that we had too many of (Stella Duffy offered “your cancer is your fault because you eat/think/love/exercise WRONG” books; others suggested Tudors, Up lit, running and/or swimming, Books That Tell Women How To Be Women, and so on).

Publishing micro-genres have always been with us. Remember, in the wake of Longitude, that late-1990s run of biographies of inanimate objects? Or the still barely abated torrent of abuse memoirs that followed A Child Called It? More recently the success of Robert Macfarlane has produced a flowering of “new nature writing”; the prominence of H Is for Hawk spawned a nature-writing/mental-health hybrid; wild swimming books went, briefly, wild; and the efforts of Henry Marsh, Adam Kay and Paul Kalanithi mean that everyone who has ever donned surgical scrubs now seems to be writing a book about it.

The problem we have is that, amid the torrent, it’s very hard to know which of these are the good ones. The type-specimens of each of these genres are usually excellent, often path-breaking. Even the much-reviled self-help genre has the greatest philosophers of the ancient world ambling round its fountainhead. But après eux, la deluge. I have at least one nature-writer friend who’s sick of nature writing; and when not long ago I wondered to historian Ian Kershaw whether we might now have had enough books about Hitler, he made what I can only call a diplomatic face.

But what do the genres that now dominate the trade publishing market tell us? It’s not too hard to see why we get a lot of books about Trump, diversity and mental health, refugee memoirs and books about economic and ecological catastrophe: these are the issues of the moment. But as to the others, and to the prevalent style of the books, with their categorical claims and their listicle titles, there’s a chinstrokey answer and a practical one.

The chinstrokey answer – tentative though it has to be – is that in an age in which “lived experience”, personal testimony and feelings have found themselves at the centre of the political economy, we’ll find them booming in the publishing economy too. And that the large number of books that make confident predictions about the future, that offer totalising explanations about how we reached the here and now (it’s all down to genes, or one commodity, or 12 key battles), that promise to encapsulate the human condition in 356 friendly pages, that will give you an easy-to-grasp handle on the basic laws of the universe, or that offer a formula for transformative personal change, are reassuring in an anxious world.

The practical explanation is that me-too-ism offers reassurance to publishers in an anxious market. Whenever a book makes a big success, publishers scour the nation waving chequebooks – “Anyone here ever felt depressed and cheered up when they met a flower/Scottish lake/water vole?” – and the fruits of their search hit WH Smith 18 months later. Also, books about ideas or personal experiences tend to be easier to write and harder to falsify than books about things – which makes them cheaper and quicker to produce than big scholarly biographies or proper complicated history.

Did Ecclesiastes have it right? “And further, by these, my son, be admonished: of making many books there is no end; and much study is a weariness of the flesh.” Or Larkin? “Get stewed. Books are a load of crap.” Not quite. It’s all good. I and the many like me will keep opening our post, and do so with only occasionally weary gratitude. It’s always better to have too many books than too few.

• Sam Leith is literary editor of the Spectator