I hadn't heard of Knox at all before my visitor sent me his book. I find Knox was a prolific writer, and he and Chesterton were mutual influences on each other. This in turn suggests to me that 20th century intellectual history is highly deficient -- it acknowledges JRR Tolkien and CS Lewis, begrudgingly notes Chesterton and Waugh, but ignores Kinsman, Knox, and Fulton Sheen. Or for that matter, Edward Feser. There's much to do.
I'm still reading The Belief of Catholics. First published in 1927, it seems to be a survey of where Catholicism stands in Anglophone culture in the first part of the century. In particular, it was written from a perspective much like that of Kinsman, an Oxonian who'd risen into Anglo-Catholic clerical ranks when Anglo-Catholicism was at its high water mark, but neither found Anglo-Catholicism satisfactory.
Knox has a chapter entitled "The Shop Window", in which he reviews factors in Catholicism that make it attractive, or at least interesting, to non-Catholics. Of Anglo-Catholicism, he says,
Of all the features in the Catholic system which appeal powerfully to men's minds at the present moment, the least, assuredly, is the mere beauty of her external adornment; the merely aesthetic effect of vestments made in art stuffs, of blazing candles, of gold and silver altar furniture, of lace and flowers. Chloe and Clorinda did feel, I think, a sneaking attraction towards these Romish bedizzenments, tempered, of course, by a strong moral reprobation. In our day, their appeal is of the slightest. If for no other reason, because these characteristics of our own system are easily imitable and have been freely imitated. It is, perhaps fortunately, no longer necessary to betake yourself to Catholic churches in order to glut your senses with artistic appreciation of ceremonial. Our High Church friends do it as well or better; their churches provide, as it were, a mimic Riviera on the soil of home to suit these sickly temperaments. Mere beauty, mere pageantry, is no speciality of ours, and no appreciable boast.This suggests to me that Anglicanorum coetibus essentially misunderstands the "precious treasures of the Anglican spiritual patrimony", which even its proponents acknowledge is liturgy, which is to say pomp and ceremonial. If that's what people want, they can get even more of it, even now, at urban TEC Anglo-Catholic parishes, and in fact, the full pomp and ceremony can be provided at only a dozen OCSP parishes at best. Clearly the liturgical authorities wanted the thees and thous, the vouchsafes and meekly kneelings, and rejected outright any special use of plain language.
This isn't the way to sell the product, something Knox clearly understood.