It used to be you could find a box of photos or keepsakes that you inherited to look back on how things were or when you were a kid. Now, most of that is stored on phones, and most parents probably don’t think to share or save them in a way to be passed down in the future.
Probably less than the moments that are lost in time before the invention of the digital camera.
Those chemical photos are going to mostly fade into nothing within a few hundred years.
Bit rot happens to digital copies. It’s slower than what happens to physical copies, but over long enough time can also lead to data loss.
Digital loss definitely happens, but with a tiny bit of care, it can be absolutely prevented.