I can assure you that Cincinnati Bell and SNET were well aware that
> they were "associated" companies, not subsidiaries. ...
Given that, did they buy exclusively from Western Electric or shop around at Automatic Electric, Kellogg, Leich, Stromberg, and overseas suppliers as well? In their situation, they had a bargaining advtg with WE that the others didn't: "well, AE wants only $xx for a Strowger unit but you want more. Will you match AE's price?"
(Of course, from 1940 onward I think W/E had more business than it could handle from the war and postwar growth.)