Not sure about the sourcing out of parts by mfgs. caused closings. Iver Johnson made most the parts for the bicycles they sold.They went under right around ww2. After ww1 quite a few bicycle mfgs.closed after making munitions for gov. and great Depression set in. Shelby,Colson,Columbia,D.P.Harris, and a few others struggled through. Dayton ,Davis went under then came back.