To clarify, I don't hate or get mad at those old folks. As you said, it was not long ago that if you didn't fill rest of the hours of day remaining after eating and sleeping, you didn't survive. It was a different time/historical context. They didn't have much of a choice.
But, I kinda find the same approach pitiful when it's used by late-middle-aged folks as a judgmental measuring stick against younger people. Unlike their parents, late-middle-aged folks had choice for building a more independent self-worth and identity, but they found it safer to completely buy in to the rhetoric of businesses/firms. And find solace in projecting their mistake onto the young, instead of contemplating on it and passing down better advice.
Historically speaking, it is really difficult to surpass the contextual limits of one's lifetime and be truly foresighted. Still, it doesn't take too much effort to be a little self-aware and contemplative, and not be a judgmental prick to people younger than you.