I did some investigating into this name. From what I've read, the name was first introduced by Eagle Brand condensed milk company. The recipe was printed on the back of the cans and the name apparently was created by Gail Borden, the owner of the company. These bars then became known by other names. Presumably by other companies who wanted to profit off their popularity but couldn't call it the same name: Hello Dolly Bars (named after a popular musical at the time) and Seven Layer Bars are all names created by competing condensed milk companies. So you may know these bars by one of those other names.