Middlebrow is not kind as I understand the word...
Googled it and these are some descriptions ---
"relating to or intended for people who are interested in art, literature, etc., that is not very serious and that is easy to understand."
"The term middlebrow describes middlebrow art, which is easily accessible art, usually popular literature, and middlebrow people who use the arts to acquire the social capital of "culture and class" and thus a good reputation. First used in the British satire magazine Punch in 1925, the term middlebrow is the intellectual, intermediary brow between the highbrow and the lowbrow forms of culture..."
From Virginia Woolf, "As a social critic, Woolf criticizes middlebrows as petty purveyors of highbrow culture for their own shallow benefit. Rather than select and read books for their intrinsic cultural value, middlebrow people select and read books they are told are the best books to read: "We highbrows read what we like and do what we like and praise what we like." Middlebrows are concerned with appearances, with how their social activities make them appear to the community, unlike the highbrows, the avant-garde men and women who act according to their commitment to the beauty and forms of art, and to values and integrity. Likewise, a lowbrow person is devoted to a singular interest, a person "of thoroughbred vitality who rides his body in pursuit of a living at a gallop across life"; and, therefore, the lowbrow are equally worthy of reverence, as they, too, are living for what they intrinsically know as valuable."
Middlebrow or not years back, in the '40s and '50s into the '60s and early '70s at least one of Edna Ferber's books was studied in High School English Lit. along with Shakespeare, Voltaire, von Strassburg (13th century poet, Tristram and Isolde) and Chaucer. Cimarron was one of the books or So Big - not so much Show Boat or Giant - she was before her time writing in characters that in the US were separate because of 'race, color or creed' - many of us enjoy a movie using a Shakespeare play as much as we enjoyed movies that the script was from a book including the writings of Feber and so if the definition of Middlebrow includes that an author's work became a box office ticket selling movie then we have to include a few authors considered Highbrow.
Frankly cannot believe in this day and age anyone much less a critic would stoop to using this terminology but then I'm finding humans are always a surprise...