As a retired commercial photographer who also shot a few hundred gigs of 1080p at the end, I had this issue when I converted to digital in 2000 and again when I retired in 2012.
For my clients, I gave them the hard drives, cables and power supplies when I closed up shop. (those I could find)
Smaller clients (weddings and family's) were given the CD-R and DVD's, I kept a backup on (3x) hard drives. Could not find more than half the clients, I will hang on to them indefinitely. (I had a bride contact me 10 years after the fact for pics of her mom at the wedding, she had died and they wanted all I had.)
My personal stuff is on hard drives and SSD's. SSD's are shelf stable for a 50 years at least.
Yes, My filing/labeling system is pretty good. Not perfect, but I can find anything in a few minutes to a an hour.
I still have a decade's worth of 35mm and 120mm film, unscanned. I looked at some of it last year after 20+ years in storage (kept in an Air Con'ed room and air tight containers) and they held up very well.
Most of that stuff is not worth a tinker's dam to anyone, but I keep it anyways.
As technology progress I will address it in the future. I probably have a few hundred terabytes already and 2x that in unscanned film, so the cloud is not a serious option for long term storage. I do use private setting on facebook photo storage for any client who needs it right now. Seems to work. But no guarantee of privacy.
All this is contingent on my memory holding out. I recently got diagnosed with TBI. (traumatic brain injury) So if I remember, I will stay abreast of new technologies and such.