It’s pretty dependent on humidity and temperature, so a DVD buried in a well sealed plastic bag with a desiccant packs is actually in good conditions. No light, generally cool, and low humidity are perfect.

A hard drive has a lot of moving parts that must work and are basically impossible to replace. With optical media you’re just storing the platters, and I’m sure you’ll still be able to track down a drive somewhere. You can still find VHS players and those have been obsolete for 25 years.