Yes, the older ones of the rotating backups are still readable.

But that's not even the actual problem nowadays: CDs and DVDs were nice when their size was still relevant in comparison to usual amounts of data. The real problem behind their decay is that we are lacking a widely available, properly scaled backup solution for more than a decade. So the mean reason people have now unreadable optical data is that they stopped thinking about it a long time ago for an utter lack of options.

I can confirm, found an old disk from ~15 years ago, was excited to see what was on it. In a jewel case and everything, but completely unreadable :(

Just had this thought, and realized all my backups had been through a flood. I wound up with several damaged disks, but was able to get all the content off of them, damage was to the outside edges, and most of them didn’t have much data written.

I have a Blu-ray burner, but I’ve never burned one (only a couple DVD’s). Probably never will.

Reminder to plug in any flash media (thumb drives, ssds) from time to time

They can also start to lose data after a couple years without power

Still got a shelf full of 360 discs, I refuse to open them and hope that the cases they’re in protect them for life longer than mine.

A small handful of my burned CDs from 20 years ago are unbearable and as far as I can tell, none of my pressed CDs are. I'm sure they'll rot eventually but I think your average cd is quite robust. Still, there's no excuse not to have backups!

I still refuse to believe in disc rot until I see it happen to me. Until that occurs, I will consider it a urban computer myth.