I'm pretty sure I still have a CD/DVD burner (is that what they were/are called?)
It looks like the most "correct" term would be recorder, but everybody just calls them burners so, yes, that's what they're called :)
Am I remembering correctly that writing/burning one is a one-time even, i.e. you can't add more later? Was a file system created thereupon at the same time?
For my usecase, yes, but multi-session disks (basically, "half-written" disks with some very simple journaling thrown in) were definitely a thing for CDs. I haven't properly investigated whether an equivalent exists for BD-Rs but it looks like it from a quick search.
Also, there are BD-REs, (Recordable Erasable) which are just like CD-RWs (ReWritable), but apparently they're less durable in the long term (and personally a bit scary to handle, imagine overwriting one by accident, the "Write Once Read Many" aspect is a feature IMO).
From what I can tell, Blu-Rays are a quite niche market (the burner costed a bit and I had to order the disks from a weird specialized local seller to get a good price), but they're definitely not dead (I just bought a USB-C burner!). It also looks like the whole market is archival-oriented so I think that's a good sign :D
All I know is that once meaningful data/content loses its pull much more quickly than discs lose their data.
For example, I'll take (this happened yesterday) spending time seeing the youngest grandchild taking first steps letting go of the swimming pool ladder rail - with looks and facial expressions of infinite wonder peppered with mild fear and/or indecision - over digging through formerly meaningful "content" that at best might occasionally evoke a few moments of "oh yeah... *that*...".
In a way, storage solutions provide ways to put a lot of effort into saving content for a person we'll no longer be anyway. We forget that although the content won't change, we will. We would have to save the current state of ourselves alongside instances of same-time-frame content, then be able to reload that state, and *then* dive into said content to fully appreciate it.
But maybe there's a way to sufficiently categorize "who I am right now" in a way that revisiting it could approach "reloading it unto becoming it"? It would take a lot of imagination and denial (of current state), perhaps something akin to "The Method" in acting? So one would first digest a file containing a sufficiently robust description of "self" at the time, and said "method" would seemingly "make it so"... and than one would quickly digest the All Important Content before doubts about truly being the former instantiation of self started setting in to wreck the, well.. *delusional* party....
It's comprickated, this individuality thang! :-)