A "pervasive myth" refers to a widely believed story or idea that has spread throughout a society and is often accepted as true, even though it may not be based on facts or evidence. Full definition
This is one of the most pervasive myths in modern society. (fitnessandpower.com)
One pervasive myth in the insurance world is that particular kinds of cars, such as SUVs or sports cars, cost more to insure because they encourage dangerous or expensive driving. (pocketsense.com)
One of the most pervasive myths about credit cards is that you need to be in debt to build or improve your credit. (smartasset.com)