It’s not a myth so much as a boondoggle.

boondoggle /boo͞n′dô″gəl, -dŏg″əl/ noun

1. An unnecessary or wasteful project or activity.
2. A braided leather cord worn as a decoration especially by Boy Scouts.
3. A cord of braided leather, fabric, or plastic strips made by a child as a project to keep busy.