From a commercial point of view, if Christmas did not exist it would be necessary to invent it.

Whitehorn’s quip reframes Christmas less as a sacred or sentimental occasion than as an economic institution. By saying it would need to be “invented,” she implies that commercial systems benefit from (and perhaps quietly depend on) a socially universalized ritual that legitimizes extraordinary consumption—gift-buying, travel, food, decorations—on a fixed annual schedule. The humor lies in treating a centuries-old festival as if it were a marketing strategy, while the sting is a critique of how commerce can appropriate tradition. The line also suggests ambivalence: even if one is skeptical of consumerism, the commercial “usefulness” of Christmas is undeniable in modern economies.