Perhaps they don't know how to take care of them. I have a mower that's 30 years old and another that's over 10. They are not high-end models (neither exist today to check prices). It's a shame people throw our perfectly good equipment because they can't keep it running, lawnmowers or otherwise.

If your argument is that a decent mower can go 20 years, then that excludes battery powered ones. You'll need to replace the batteries.