Jack Sprat and his wife

I saw a picture of a 1950s station on Faze that had a Hammarlund receiver similar to this:

source: https://www.ebay.com/itm/136778372006

and a Johnson Viking transmitter similar to this:

11 meters ?

source: https://www.ebay.com/itm/297845200608

And I thought of this:

Jack Sprat could eat no fat, 
his wife could eat no lean; 
and so between the two of them, 
they licked the platter clean

Isn't it strange that some of the radio companies were kinda like that?  Hammarlund made receivers almost exclusively.  EF Johnson made transmitters almost exclusively.  Certainly Collins, Hallicrafters and the rest felt free to sell both receivers and transmitters.

I wonder why at least those two decided to "Jack Sprat" it ?

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm