DNA in living cells has some fragility because it is in an aqueous solution and also actively used to generate RNA. DNA out side of cells is even more fragile, it will inevitably be eaten by bacteria. But put DNA in the right sterile environment, it can last for thousands of years and has great resistance to electromagnetic interference.
This has echos of No True Scotsman. Computer storage media also have ideal conditions that can be used to extend their lifetimes (though, granted, not indefinitely, AFAIK).
What about in real conditions, subject to things like temperature variations (including "extreme" heat that non-operating computer hardware can do just fine in), exposure to light, humidity from the air (to put it back into aqueous solution occasionally), and common oxiders found floating around in the air?
Could one rely on an arbitrary single strand to last even 5 years in an office environment, or are numerous, RAID1-style, copies required to maintain fidelity?