Hey, Snip, glad to see you back. When people use the cheaper alternative, sometimes it is because going with more expensive means going without, period. My parents are doing quite well now, but only because Mom could always make a dime go where most people needed a dollar. By the way, my sibs and I are all in our fifties (I'm the eldest and pushing 60) and none have suffered any dire diseases because we grew up on margarine. And, I have to say, some of us still prefer margarine to butter, and salad dressing (i.e., brand name Miracle Whip, but Mom never bought a brand name anything if something else was cheaper) instead of mayonaise.
She also used to buy "GI brand" canned goods. That was before stores had store brands. At the commissary you'd find cans of food that were unlabelled and just stamped something like, Beans, Green, SN#12341533. One day she bought a can of "Peas, Green", got them home and realized they were La Soeur baby peas (the best of the best in canned peas in those days). She got back in the car and bought a case! (most of the "GI Brand" stores were excess stuff that the companies sold to the military at cut rates).