As he explains, Mego sought to diversify it's market "We thought (with the Waltons) it was family, we'd get a younger child interested in action figures and it had enormous popularity at that time. So we took a shot at it
Mr. Kublan also explained that because Mego was "The Chosen One" in terms of lisencing that they were offered the Waltons very cheaply, add that with the economy of the 8" body and you have a pretty safe bet.