The made-up name gained so much respect and credibility that the company just went along with it. For the radio show, each station had a different woman to be the voice of "Betty," but all read from a script developed by the home office. As for the portraits, well, this explains how she could look like a 30-something housewife in the '40s and a still-30-something yuppie in the '80s, short of her being Doctor Who.
So that brownie mix doesn't grant immortality? This is bullshit.
And people of all ages still believe in her today. The writer of Finding Betty Crocker: The Secret Life of America's First Lady of Food did a little survey and says that about half the people she talked to believed that Betty Crocker was a real person, or that she existed at some point. Hell, just do a Google search and you'll find plenty of disheartening evidence.
Via Yahoo Answers