Fragmentation of Data
There is no universal name or a term for this phenomenon (at least none that I'm aware of), but I am quite certain people can relate to it and have encountered similar conundrums. There are analogous conundrums when one lives in a home with many rooms and "way too much stuff" in them (too many items to keep abreast of). Humans love to hoard, but at the same time the typically "conformist" human mind seeks solitude through simplicity (reducing mental fatigue or overload); those are competing desires. Some people spent a lifetime collecting, then decide to "share away" in pursuit of minimalism. It happens all the time.
When you're a very young person you're not quite aware of data retention or value your data enough to ensure it remains available (to you) some time in the future. When I say "young person" I mean under 10. To many people these days that would mean photos or videos.
A lot of data gets lost forever all the time. We're swimming in data. The planet is drowning in data.
Then there's my own experience. In the 90s it wasn't quite feasible to keep all your data, especially multimedia. Drives just didn't have high capacity. Retaining all your USENET data, for example, even if it was just plain text, would require multiple drives, maybe even external cassettes. Some of these cassettes would not even last long and format shifting would be required.
I've long been tidy with my files, even with old E-mail folders, which go back almost to the 1990s (back then my E-mails were not so important to anyone; not much value in what a teenager says to friends). I tried to keep the important files (such as my code, photos, projects) compact enough to make backups fast. But that became harder for two reasons: 1) human memory is limited and its time span also has limits (so one can forget where to find what; you may be able to remember all "the places" today, but will you remember it next year or in 5 years?); 2) No machine lasts forever, so one can end up with many backups and it's hard to remember which machine, drive, OS, partition, backup drive etc. some data is stored on, which in turn relates to (1).
I've never established or found any good solution to this problem. The human brain just isn't very good at retaining knowledge for several decades; storage devices aren't good at it either. Thankfully, storage technology makes advances, so for a given price the storage capacity grows over time. The new storage devices sort of "swallow" the data or prior storage devices "wholesale". So some place or another the old files probably still exist and are in good enough integrity (condition).
I'm in my 40s now and I can only envision that by the time I'm 60 or 70 it'll be very difficult to remember where I put code that I wrote in my 20s or how exactly my old photos are organised. So over time I realised that I no longer need to obsess over collecting and archiving too much data. It adds up and becomes a complex task. What typically matters most is the material polished enough (code, articles, photos) to be made public, e.g. in some Git repository, a Web site, a Gemini capsule.
Life is too short to "hoard" data. The brain cannot keep up, even if storage devices can. We're not robots, and moreover there are limits to how much robots can assist us. █