It isn't just languages that pass out of existence. I know a lot about my parents, probably about .1% of that about my grandparents, and pretty much nothing going back further than that. There are essentially no records. What kind of lives they lived, what was important to them, how they viewed the world, etc., all gone.

If one of your ancestors was a historical figure, or kept a diary, maybe you have much more. But that's hardly ordinary.

It's just the way things are, and probably the way it has to be.