Considering the generation of lost photos between film cameras with their physical photos and smart phones auto uploading pictures to a server.
I can only speak for myself, but I can't even imagine how many photos I've lost to that period of time where you had to actually save all your digital photos on a computer. So many photos lost to upgrading computers or failing hard drives. Most of them unfortunately from my formative years that I barely remember.
Nearly everything between my toddler years and mid to late teens is just gone.