Did they? Save for stuff in safe deposit boxes (I can't remember what happens to that when you die), everything was likely to be in your home somewhere, pretty trivially accessible unless you use a safe or secret compartments or something.
No the sheer disrespect shown by companies for their customers data and the fact that it is a lot easier to loose digital data than anything else have increased the problem.
This could end up being just another one of those dark ages in history where very little can be found since everything was digital and most of it was just deleted in an effort to reuse space or discarded by companies who went bankrupt or got bought out.
I don't buy the "dark ages" thing. Even if 99.99% of the digital data about you disappears, you'll still leave a much, much bigger footprint than even your recent ancestors did. I know a lot about my parents, a few bits and pieces about my grandparents, and nothing further back except a name and maybe a photo.