Sears-Roebuck Foundation question

[Chad123]

After Episode 1655, The Sears-Roebuck Foundation stopped funding Mister Rogers' Neighborhood. Starting with Episode 1656, the sponsors for the show were reduced to Public Television Stations and The Corporation for Public Broadcasting. Why did The Sears-Roebuck Foundation decide to eventually stop sponsoring the show? Does anyone know, because I certainly don't.