"Trends come and go, but the best seller remains essentially serendipitous. An editor can be no more certain of finding the next one than a writer can be assured of writing it. "As a rule of thumb," writes John Sutherland, an English scholar who has studied the phenomenon, "what defines the bestseller is bestselling. Nothing else."
"The term best seller has always been a misnomer. Fast seller would be more appropriate, since the pace of sales matters as much as the quantity. The first list of books "in order of demand" was created in 1895 by Harry Thurston Peck, editor of the trade magazine The Bookman.
From the start, Peck seems to have had mixed feelings about the arbitrariness of the mechanism he had chosen to anoint books. "The period during which a popular novel enjoys favor is growing shorter all the time nowadays," he wrote in 1902, lamenting "the flood of fiction that is being placed upon the market and vigorously promoted practically every month in the year."
Over time, however, shorter becomes not only the period 'during which a popular novel enjoys favor', or a list of authors who enjoy the mega-popularity, but limited becomes the choice of genres:
"A combination of factors brought about the homogenization of the best-seller list that began in the late '70s and continues today. [...] the "superstores" pioneered by Barnes & Noble began to edge independents out of the market, which made publishers less inclined to publish the quirkier fiction in which the smaller bookstores specialized. Meanwhile, the conglomeration of publishing houses under larger and larger umbrellas meant that profits were often managed by distant executives who prioritized the bottom line over promoting literary culture, making editors less likely than ever to take risks on anything beyond the mainstream. The result was that for a new author, making the best-seller list was more like winning the lottery than ever before—in terms of both payout and probability."
Market favors writers-manufacturers who mass-produce books:
"With the regulars bringing out a new book every year or so, the number of open slots naturally decreased. And so a novel by a new writer has a smaller chance of becoming a best seller today than at any other time in history."
Source: bookforum.com, Nov. 30, 2010