It can be easy to lament the lack of family history items such as photographs, bibles, letters, etc. that some families seem to have and other do not. I understand the frustration of those who have no such items in their family.
I also understand how it sometimes comes to be that these items do not get passed down from one generation to the next. Some families never really have these items in the first place for one reason or another. Other times they are passed down in the family and for one reason or another either leave the family, are unidentifiable, or are destroyed.
Having been involved in several post-death house or apartment cleanings it is easy to see how this can sometimes happen. Sometimes these cleanings are done under an extremely tight time frame and items are unceremoniously thrown away. Sometimes these cleanings are highly emotional events where remembering is painful and it’s easier to toss than to methodically go through items one at a time. Sometimes these cleanings are done by someone who is not a member of the family and is simply working to “prepare the location for the next owner or tenant.”
Consequently, items can be thrown away, donated, incorrectly identified, have their provenance lost, etc. It happens and, even if it has never happened to you personally, it certainly is easier to see how it could happen when you have been involved in it yourself.
So if you do have items passed down from long-dead family members–consider yourself lucky. That item has survived and navigated its way to you over time and place. If you have such items, work on ways to preserve them for others.