While I am in doubt with the numbers, I agree with the trend. Writable DVDs last sometimes even less years, since they are produced so cheap.

There where the MO-Drives, that really lasted many decades, but they also vanished.

Best solution currently are the old-school tapes, since they are created as real backup-solution. Trouble is, that when you want to buy a current drive (with enough data density) you will have to invest a stack of money just for the drive. Also the equipment and tapes are seldom sold for consumers. I looked up some figures ... and one cartridge currently costs half the sum of the same hdd space (consumer drives). So even the cartridges are rather costly for consumers.