Past women most often did not get to go to school or study till a university grade. Life was taught simple, down-to-earth, and not to expect a lot.
As a woman myself, having lived under parents who had bad finance, always last priority for everything, and lived in Yemen well-known for war and impoverished state, I knew what your mom meant. I felt it just as your mom felt when she mentioned it.
People who had more often became unhappy with what they had. Because they craved for more, and more, and more. Children grown up given luxury or better foods would expect more. They didn't know what hardship was like having just a bowl of rice and a sunny egg.