I don't know if that is true. I have 5.25" floppies from ca.1990 that were readable as of just a couple years ago, so about 30 years.
You're saying flash drives are readable for at least 300 years? I don't know but I doubt that.
(The floppies might still be readable today, I just haven't tried. The content is now archived in a zfs pool.)
Maybe I've been exceptionally lucky, but I've never had a USB drive fail or act oddly. The only data-loss flash media failures I've had were microSD cards in Android phones, and an early SATA SSD.
My mom was at a public office where they would get data on floppy disks, and read issues were super common and reliability was really hit or miss, data corruption, sector errors, you name it.