Printed circuits were used in early RCA sets. The major parts cost was in the picture tube, and that was reduced only slowly over the years. Of course, there were also more parts in total than black and white. The manufacture of the sets itself took more set-up labor than a black and white set. So, although there were cost reductions, most of those except for the color tube could be applied to black and white sets too. As stated above, the overhead costs per set were reduced when volume increased.
The history of TV prices is one of either being constant or decreasing while general inflation increased the prices of everything else. So, the inflation-adjusted price was always decreasing, sometimes fairly rapidly and other times very rapidly. This was a positive feedback loop in the market, with falling real prices spurring sales and increased production reducing costs. The adoption curves showed the expected result, with one B&W TV per household, then multiple B and W, then color, then multiple color sets. Both B&W and color showed this "S-shaped" curve of number of households with sets, B&W in the late 40s and color in the mid-late 60s.
correction: if you consider the mid-points of the durves rather than the first upturn, it was the early 50s for B&W and early 70s for color:
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