It seemed as if every time you met a person from a new department, you heard of new swindles and new crimes. There was, for instance, a Lithuanian who was a cattle-butcher for the plant where Marija had worked, which killed meat for canning only; and to hear this man describe the animals which came to his place would have been worth while for a Dante or a Zola. It seemed that they must have agencies all over the country, to hunt out old and crippled and diseased cattle to be canned. There were cattle which had been fed on “whiskey-malt,” the refuse of the breweries, and had become what the men called “steerly”—which means covered with boils. It was a nasty job killing these, for when you plunged your knife into them they would burst and splash foul-smelling stuff into your face; and when a man’s sleeves were smeared with blood, and his hands steeped in it, how was he ever to wipe his face, or to clear his eyes so that he could see?
So, one motivation behind the much-derided traditional cuisine of mid-20th Century Americans was an attempt to avoid being swindled by unscrupulous businessmen.
Another point about mid-Century cuisine served in middle class homes is that much of it was modeled on business dining in restaurants, meals served to people who might not have all that much in common but who want to develop a friendlier relationship. Business dining was in contrast to exploratory dining among people who already are friends and who have already dined together and who find their tastes are enough in sync to want to explore cuisines together.
So, business cuisine in 1950 had a high emphasis on common denominator foods (e.g., steak and potatoes) that wouldn't be likely to weird out a customer. In turn, that had a lot of influence on what people ate at home. In general, the goal of mid-Century American culture was to create a friendly, open, fairly egalitarian, non-exclusionary society in which Americans would feel comfortable doing business with each other across a vast continent. This influenced norms toward some degree of homogeneity, blandness, and conformity in minor matters like cuisine, but was overall such an enormous success in terms of prosperity and national solidarity that we've forgotten the reasons behind many of the details, and thus view this culture with ignorant contempt.