How come that beside RCA's there are just a few '50's color sets preserved

[kx250rider]

The RCA was really the only true mass-produced color set in the 50s, but there were dozens of other brands. I've had a Raytheon 21", Motorola 19" & 21", CBS-Columbia 19", a Sparton 15", a Sentinel 21", several Hoffmans (one 19" prototype and two 21" sets), a Packard-Bell 21" , a GE 15", a Stromberg-Carlson 15", and others. All of them are rare as hens' teeth.

Charles