Loss or breakage.

I had the original AirPods and vowed to never buy them again because replacing the battery was so expensive.

Just ridiculous to throw away expensive audio equipment because battery replacement is as expensive as 50% of a new pair.

While good headphones from the 70s are still good, maybe with some foam replacements.

Loss obviously being the #1.

Dropping, and then stepping on them seems like a common failure mode.

Dirt can stop the charging, most people will just replace instead of cleaning.

Even replacing the rubber tips is probably too much to expect from most people.