Your DRM free digital song will play fine in 20 years,. A silly piece of plastic...... not so much....
Remember 78 RPM albums? Of course you don't.... that's my point.
Remember 33 1/3 RPM albums? Maybe, listen to any lately?
Remember 45 RPM singles? Maybe, listen to any lately?
Digital can be converted to whatever the next format is.... and thus played on future players. CD's are a wastedof money.... they wear out, warp, oxidize.... etc.