Parents in the past did not know much about investment, so they preferred to save their money even though it would be eroded by inflation which would lose its value over time. The only option I often hear is gold and that is only done by a small number of people.
Now investment should be something that is no longer foreign to parents, so they can learn it and teach it to their children. Moreover, in this era, it is not difficult to find information amidst massive digital developments.
For most people, it's true that in ancient times, they weren't very smart, at least most of them weren't, and even though they had enough money, they never used it the right way. I never needed to go far to understand this because my own family, my father and grandfather, they had so much money back in the day that they could buy anything if they wanted, and they could quite literally buy acres of land if they wanted, but they didn't do it because they never thought how useful it can be for them and for their children in the future.
Today, we can see the places or lands that were up for sale at that time and they didn't buy them even though they could easily afford it, they have so much value today but they aren't ours because our ancestors didn't know where they should invest their money, and most of them only wasted the money on the present instead of thinking about the future.